Remove a background of one's own

- A cross on the tile's top-right corner removes an added background, critical-coloured at rest and named by its tooltip, as design draws it. The one in force offers none, since taking it away would leave nothing chosen; the view model refuses it too. - The cross sits beside the item rather than in it, which would take the press first and choose the tile, and isn't a control of its own, so the menu keeps one keyboard model: Delete or Backspace on the tile does the same, and the tile says so with aria-keyshortcuts. - Removed from IndexedDB and its picture released. End to end on Chromium and Firefox, a background removed by Delete is still gone after a reload. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Merge pull request #4288 from element-hq/spec/background-effects/8-own-backgrounds
2026-11-07 00:52:28 +00:00 · 2026-11-06 10:33:22 +01:00 · 2026-11-06 10:33:17 +01:00 · 2026-11-06 07:24:53 +00:00 · 2026-11-05 16:30:40 +01:00 · 2026-11-05 16:20:33 +01:00
28 changed files with 2277 additions and 114 deletions
@@ -19,7 +19,7 @@ services:
      - ./backend/playwright_homeserver-othersite.yaml:/data/cfg/homeserver.yaml:Z
  element-web:
    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
-    image: ghcr.io/element-hq/element-web:develop@sha256:a79801206c628a912d57fa6f355d5c5ab9c6c40c2d1b6208d4192678fb6e80c7
+    image: ghcr.io/element-hq/element-web:develop@sha256:e063472b6bdf6d0bfa1d43dfa4ef7effee1efd2c9684daee665d1bedfe746a47
  element-web-1:
    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
-    image: ghcr.io/element-hq/element-web:develop@sha256:a79801206c628a912d57fa6f355d5c5ab9c6c40c2d1b6208d4192678fb6e80c7
+    image: ghcr.io/element-hq/element-web:develop@sha256:e063472b6bdf6d0bfa1d43dfa4ef7effee1efd2c9684daee665d1bedfe746a47
@@ -3,6 +3,7 @@
    "user_menu": "User menu"
  },
  "action": {
+    "add_background_image": "Add image",
    "close": "Close",
    "copy_link": "Copy link",
    "edit": "Edit",
@@ -98,6 +99,10 @@
  },
  "disconnected_banner": "Connectivity to the server has been lost.",
  "error": {
+    "background_animated": "Animated images cannot be used as a background",
+    "background_not_an_image": "That file is not a supported image",
+    "background_not_kept": "That background could not be saved",
+    "background_undecodable": "That image could not be opened",
    "call_is_not_supported": "Call is not supported",
    "call_not_found": "Call not found",
    "call_not_found_description": "<0>That link doesn't appear to belong to any existing call. Check that you have the right link, or <2>create a new one</2>.</0>",
@@ -97,6 +97,7 @@
    "copy-to-clipboard": "^3.3.3",
    "eslint-plugin-element-call": "link:eslint",
    "eslint-plugin-storybook": "^10.3.6",
+    "fake-indexeddb": "^6.2.5",
    "fetch-mock": "11.1.5",
    "i18next": "^26.0.0",
    "i18next-browser-languagedetector": "^8.0.0",
@@ -5,9 +5,15 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */

-import { expect, test, type Locator, type Page } from "@playwright/test";
+import { expect, test, type Browser, type Page } from "@playwright/test";

 import { SpaHelpers } from "./spa-helpers.ts";
+import {
+  averageColour,
+  cameraColour,
+  type Colour,
+  distance,
+} from "./utils/colour.ts";

 // Background effects need WebGL2, and headless Firefox on a CI runner has none,
 // so it rightly offers none of them.
@@ -16,15 +22,13 @@ test.skip(
  "Background effects need WebGL2, which headless Firefox on CI does not have",
 );

-type Colour = [number, number, number];
-
 test.describe("background effects", () => {
  test("pre-join preview shows the chosen effect", async ({ page }) => {
    test.slow();
    await page.goto("/");
    await SpaHelpers.createCall(page, "Effect user", "Background effects");
    const preview = page.locator("video").first();
-    const camera = await averageColour(preview);
+    const camera = await cameraColour(preview);

    await page.getByRole("button", { name: "Camera", exact: true }).click();
    const tile = page
@@ -102,25 +106,747 @@ async function drawsPerSecond(page: Page): Promise<number> {
  });
 }

-/** The mean colour of a video's current frame or an image, drawn small. */
-async function averageColour(element: Locator): Promise<Colour> {
-  return element.evaluate(
-    async (source: HTMLVideoElement | HTMLImageElement) => {
-      if (source instanceof HTMLImageElement) await source.decode();
-      const canvas = document.createElement("canvas");
-      canvas.width = canvas.height = 32;
-      const context = canvas.getContext("2d")!;
-      context.drawImage(source, 0, 0, 32, 32);
-      const { data } = context.getImageData(0, 0, 32, 32);
-      const sum = [0, 0, 0];
-      for (let i = 0; i < data.length; i += 4)
-        for (let c = 0; c < 3; c++) sum[c] += data[i + c];
-      const pixels = data.length / 4;
-      return sum.map((s) => s / pixels) as Colour;
-    },
-  );
+test.describe("background effects section", () => {
+  test("section stays within the call area at every size", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Sizes user", "Background effect sizes");
+
+    for (const size of [
+      { width: 1280, height: 800 },
+      { width: 800, height: 600 },
+      { width: 600, height: 420 },
+      { width: 480, height: 360 },
+      { width: 360, height: 640 },
+    ]) {
+      await page.setViewportSize(size);
+      await page.getByRole("button", { name: "Camera", exact: true }).click();
+      const menu = page.getByRole("menu");
+      await expect(menu).toBeVisible();
+
+      const box = (await menu.boundingBox())!;
+      const where = `at ${size.width}x${size.height}`;
+      expect(box.x, where).toBeGreaterThanOrEqual(0);
+      expect(box.y, where).toBeGreaterThanOrEqual(0);
+      expect(box.x + box.width, where).toBeLessThanOrEqual(size.width);
+      expect(box.y + box.height, where).toBeLessThanOrEqual(size.height);
+
+      const last = page
+        .getByRole("group", { name: "Background effects" })
+        .getByRole("menuitemradio")
+        .last();
+      await last.scrollIntoViewIfNeeded();
+      await expect(last, where).toBeInViewport({ ratio: 1 });
+      await last.click();
+      await expect(last, where).toHaveAttribute("aria-checked", "true");
+
+      // Back to no effect for the next size, and close.
+      await page
+        .getByRole("group", { name: "Background effects" })
+        .getByRole("menuitemradio", { name: "None" })
+        .click();
+      await page.keyboard.press("Escape");
+      await expect(menu).toBeHidden();
+    }
+  });
+});
+
+test.describe("the chosen effect", () => {
+  test("chosen effect survives leaving and rejoining", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Returning user", "Effect remembered");
+    const { camera, picture } = await chooseAndWear(page, "Background 1");
+    await page.getByTestId("lobby_joinCall").click();
+    await page.getByTestId("incall_leave").click();
+    await expect(page.getByRole("heading")).toContainText(
+      "your call has ended",
+    );
+
+    await page.goto("/");
+    await page.getByTestId("home_callName").fill("Effect remembered again");
+    await page.getByTestId("home_go").click();
+    await expect(page.getByTestId("lobby_joinCall")).toBeVisible();
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+    const tile = page
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 1" });
+    await expect(tile).toHaveAttribute("aria-checked", "true");
+    const preview = page.locator("video").first();
+    await expect
+      .poll(async () => distance(await averageColour(preview), picture), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, picture) / 2);
+  });
+
+  test("second session still shows the existing error", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Two tabs", "Effect in two tabs");
+    await chooseAndWear(page, "Background 1");
+
+    const second = await page.context().newPage();
+    await second.goto("/");
+    await expect(
+      page.getByRole("heading", { name: "Opened in another tab" }),
+    ).toBeVisible();
+  });
+});
+
+/** Chooses an effect in the lobby, and waits until the preview wears it. */
+async function chooseAndWear(
+  page: Page,
+  name: string,
+): Promise<{ camera: Colour; picture: Colour }> {
+  const preview = page.locator("video").first();
+  const camera = await cameraColour(preview);
+  await page.getByRole("button", { name: "Camera", exact: true }).click();
+  const tile = page.getByRole("menuitemradio", { name });
+  await tile.click();
+  const picture = await averageColour(tile.locator("img"));
+  await expect
+    .poll(async () => distance(await averageColour(preview), picture), {
+      timeout: 60_000,
+    })
+    .toBeLessThan(distance(camera, picture) / 2);
+  await page.keyboard.press("Escape");
+  return { camera, picture };
 }

-function distance(a: Colour, b: Colour): number {
-  return Math.hypot(a[0] - b[0], a[1] - b[1], a[2] - b[2]);
+test.describe("a background of one's own", () => {
+  test("adds an image from the device", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Adding user", "Own background");
+    const preview = page.locator("video").first();
+    const camera = await cameraColour(preview);
+    const red = await redImage(page);
+
+    await addImage(page, red);
+    const mine = page
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 3" });
+    await expect(mine).toBeVisible();
+    await expect(mine).toHaveAttribute("aria-checked", "false");
+
+    await mine.click();
+    await expect
+      .poll(async () => distance(await averageColour(preview), RED), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, RED) / 2);
+  });
+
+  test("adding an image makes no upload", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Private user", "Own background kept");
+    const preview = page.locator("video").first();
+    const camera = await cameraColour(preview);
+    const red = await redImage(page);
+    const sent: { request: string; body: Buffer | null }[] = [];
+    page.on("request", (request) =>
+      sent.push({
+        request: `${request.method()} ${request.url()}`,
+        body: request.postDataBuffer(),
+      }),
+    );
+
+    await addImage(page, red);
+    await page
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 3" })
+      .click();
+    // Kept, chosen and in force: anything that would send it has had its turn.
+    await expect
+      .poll(async () => distance(await averageColour(preview), RED), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, RED) / 2);
+    // The file as given, and the copy kept, which is encoded anew.
+    const samples = [red, await keptBytes(page)].map((bytes) =>
+      bytes.subarray(bytes.length - 64),
+    );
+    const carriesIt = sent.filter(
+      ({ request, body }) =>
+        request.includes("/_matrix/media/") ||
+        samples.some((sample) => body?.includes(sample)),
+    );
+    expect(carriesIt.map(({ request }) => request)).toEqual([]);
+  });
+
+  test("added image survives rejoining and is gone after storage is cleared", async ({
+    page,
+  }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Keeping user", "Own background again");
+    const preview = page.locator("video").first();
+    const camera = await cameraColour(preview);
+    const red = await redImage(page);
+    await addImage(page, red);
+    const mine = page
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 3" });
+    await mine.click();
+    await page.keyboard.press("Escape");
+
+    await page.reload();
+    await expect(page.getByTestId("lobby_joinCall")).toBeVisible();
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+    await expect(mine).toHaveAttribute("aria-checked", "true");
+    await page.keyboard.press("Escape");
+    await expect
+      .poll(async () => distance(await averageColour(preview), RED), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, RED) / 2);
+
+    await page.evaluate(
+      async () =>
+        new Promise<void>((resolve, reject) => {
+          const request = indexedDB.deleteDatabase(
+            "element-call-background-images",
+          );
+          request.onsuccess = (): void => resolve();
+          request.onerror = (): void => reject(request.error);
+          request.onblocked = (): void => resolve();
+        }),
+    );
+    await page.reload();
+    await expect(page.getByTestId("lobby_joinCall")).toBeVisible();
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+    await expect(
+      page.getByRole("group", { name: "Background effects" }),
+    ).toBeVisible();
+    await expect(mine).toHaveCount(0);
+    await page.keyboard.press("Escape");
+
+    await addImage(page, red);
+    await expect(mine).toBeVisible();
+  });
+
+  test("a removed image stays removed", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(
+      page,
+      "Removing user",
+      "Own background removed",
+    );
+    await addImage(page, await redImage(page));
+    const mine = page
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 3" });
+    await expect(mine).toHaveAttribute("aria-keyshortcuts", "Delete");
+    await mine.focus();
+    await page.keyboard.press("Delete");
+    await expect(mine).toHaveCount(0);
+
+    await page.reload();
+    await expect(page.getByTestId("lobby_joinCall")).toBeVisible();
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+    await expect(
+      page.getByRole("group", { name: "Background effects" }),
+    ).toBeVisible();
+    await expect(mine).toHaveCount(0);
+    expect(await keptImages(page)).toEqual([]);
+  });
+});
+
+test.describe("what can be added", () => {
+  test("refuses an animated image", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Refused user", "Animated refused");
+    await addImage(page, ANIMATED_GIF, {
+      name: "moving.gif",
+      type: "image/gif",
+    });
+
+    await expect(
+      page.getByText("Animated images cannot be used as a background"),
+    ).toBeVisible();
+    const section = page.getByRole("group", { name: "Background effects" });
+    await expect(
+      section.getByRole("menuitemradio", { name: "Background 3" }),
+    ).toHaveCount(0);
+    await expect(
+      section.getByRole("menuitemradio", { name: "None" }),
+    ).toHaveAttribute("aria-checked", "true");
+    expect(await keptImages(page)).toEqual([]);
+  });
+
+  test("reduces an oversized image", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Large user", "Oversized reduced");
+    await addImage(page, await pngImage(page, { width: 4000, height: 3000 }));
+
+    await expect(
+      page
+        .getByRole("group", { name: "Background effects" })
+        .getByRole("menuitemradio", { name: "Background 3" }),
+    ).toBeVisible();
+    await expect(page.getByRole("alert")).toHaveCount(0);
+    const [kept] = await keptImages(page);
+    expect(kept).toMatchObject({ width: 1920, height: 1440 });
+  });
+
+  test("lays every image on an opaque ground", async ({ page }) => {
+    test.setTimeout(120_000);
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Logo user", "Transparent made opaque");
+    await addImage(
+      page,
+      await pngImage(page, { width: 320, height: 180, transparent: true }),
+    );
+
+    await expect(
+      page
+        .getByRole("group", { name: "Background effects" })
+        .getByRole("menuitemradio", { name: "Background 3" }),
+    ).toBeVisible();
+    const [kept] = await keptImages(page);
+    expect(kept.minAlpha).toBe(255);
+  });
+});
+
+/** Two frames of one pixel, red then blue. */
+const ANIMATED_GIF = Buffer.from(
+  "R0lGODlhAQABAPEAAP8AAAAA/wAAAAAAACH/C05FVFNDQVBFMi4wAwEAAAAh+QQACgAAACwAAAAAAQABAAACAkQBACH5BAAKAAAALAAAAAABAAEAAAICTAEAOw==",
+  "base64",
+);
+
+/** A red PNG of the given size; transparent leaves its right half empty. */
+async function pngImage(
+  page: Page,
+  size: { width: number; height: number; transparent?: boolean },
+): Promise<Buffer> {
+  const dataUrl = await page.evaluate(({ width, height, transparent }) => {
+    const canvas = document.createElement("canvas");
+    canvas.width = width;
+    canvas.height = height;
+    const context = canvas.getContext("2d")!;
+    context.fillStyle = "rgb(255, 0, 0)";
+    context.fillRect(0, 0, transparent ? width / 2 : width, height);
+    return canvas.toDataURL("image/png");
+  }, size);
+  return Buffer.from(dataUrl.split(",")[1], "base64");
+}
+
+/** The images the device keeps, as it keeps them. */
+async function keptImages(
+  page: Page,
+): Promise<{ width: number; height: number; minAlpha: number }[]> {
+  return page.evaluate(async () => {
+    const db = await new Promise<IDBDatabase>((resolve, reject) => {
+      const request = indexedDB.open("element-call-background-images");
+      request.onsuccess = (): void => resolve(request.result);
+      request.onerror = (): void => reject(request.error);
+    });
+    if (!db.objectStoreNames.contains("backgrounds")) return [];
+    const kept = await new Promise<{ image: Blob }[]>((resolve, reject) => {
+      const request = db
+        .transaction("backgrounds")
+        .objectStore("backgrounds")
+        .getAll();
+      request.onsuccess = (): void => resolve(request.result);
+      request.onerror = (): void => reject(request.error);
+    });
+    db.close();
+    return Promise.all(
+      kept.map(async ({ image }) => {
+        const bitmap = await createImageBitmap(image);
+        const canvas = new OffscreenCanvas(bitmap.width, bitmap.height);
+        const context = canvas.getContext("2d")!;
+        context.drawImage(bitmap, 0, 0);
+        const { data } = context.getImageData(
+          0,
+          0,
+          bitmap.width,
+          bitmap.height,
+        );
+        let minAlpha = 255;
+        for (let i = 3; i < data.length; i += 4)
+          minAlpha = Math.min(minAlpha, data[i]);
+        return { width: bitmap.width, height: bitmap.height, minAlpha };
+      }),
+    );
+  });
+}
+
+/** The bytes of the one image the device keeps. */
+async function keptBytes(page: Page): Promise<Buffer> {
+  const base64 = await page.evaluate(
+    async () =>
+      new Promise<string>((resolve, reject) => {
+        const open = indexedDB.open("element-call-background-images");
+        open.onerror = (): void => reject(open.error);
+        open.onsuccess = (): void => {
+          const all = open.result
+            .transaction("backgrounds")
+            .objectStore("backgrounds")
+            .getAll();
+          all.onerror = (): void => reject(all.error);
+          all.onsuccess = (): void => {
+            const reader = new FileReader();
+            reader.onload = (): void =>
+              resolve((reader.result as string).split(",")[1]);
+            reader.readAsDataURL((all.result[0] as { image: Blob }).image);
+          };
+        };
+      }),
+  );
+  return Buffer.from(base64, "base64");
+}
+
+const RED: Colour = [255, 0, 0];
+
+/** A solid red PNG, unlike the camera and the shipped pictures. */
+async function redImage(page: Page): Promise<Buffer> {
+  const dataUrl = await page.evaluate(() => {
+    const canvas = document.createElement("canvas");
+    canvas.width = 320;
+    canvas.height = 180;
+    const context = canvas.getContext("2d")!;
+    context.fillStyle = "rgb(255, 0, 0)";
+    context.fillRect(0, 0, canvas.width, canvas.height);
+    return canvas.toDataURL("image/png");
+  });
+  return Buffer.from(dataUrl.split(",")[1], "base64");
+}
+
+/** Adds an image from the camera menu's add tile, leaving the menu open. */
+async function addImage(
+  page: Page,
+  image: Buffer,
+  { name, type } = { name: "mine.png", type: "image/png" },
+): Promise<void> {
+  if (!(await page.getByRole("menu").isVisible()))
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+  const chooser = page.waitForEvent("filechooser");
+  await page.getByRole("menuitem", { name: "Add image" }).click();
+  await (await chooser).setFiles({ name, mimeType: type, buffer: image });
+}
+
+test.describe("joining with a background chosen", () => {
+  test("publishes no frame of the room", async ({ browser }) => {
+    // Two first builds of the pipeline, one of them held back.
+    test.setTimeout(180_000);
+    const hostContext = await browser.newContext();
+    const host = await hostContext.newPage();
+    await recordIncomingFrames(host);
+    await host.goto("/");
+    await SpaHelpers.createCall(host, "Host", "Join with a background", true);
+    await expect(host.getByTestId("incall_videomute")).toBeEnabled({
+      timeout: 10_000,
+    });
+    const inviteLink = await SpaHelpers.getCallInviteLink(host);
+    await host.keyboard.press("Escape");
+
+    const guestContext = await browser.newContext();
+    const guest = await guestContext.newPage();
+    await guest.goto(inviteLink);
+    await guest.getByTestId("joincall_displayName").fill("Guest");
+    await guest.getByTestId("joincall_joincall").click();
+    const preview = guest.locator("video").first();
+    await expect(preview).toBeVisible();
+    const camera = await cameraColour(preview);
+    await guest.getByRole("button", { name: "Camera", exact: true }).click();
+    const tile = guest.getByRole("menuitemradio", { name: "Background 1" });
+    await tile.click();
+    const picture = await averageColour(tile.locator("img"));
+    await expect
+      .poll(async () => distance(await averageColour(preview), picture), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, picture) / 2);
+    // Were the pipeline built again for the call's track, it would take as
+    // long as on the slower route. Routing bypasses the cache, so it waits.
+    let heldBack = 0;
+    await guest.route("**/*.tflite*", async (route) => {
+      heldBack += 1;
+      await new Promise((resolve) => setTimeout(resolve, 15_000));
+      await route.continue();
+    });
+    await guest.keyboard.press("Escape");
+    await guest.getByTestId("lobby_joinCall").click();
+
+    const guestTile = host
+      .getByTestId("videoTile")
+      .filter({ has: host.getByTestId("name_tag").getByText("Guest") });
+    await expect(guestTile.locator("video")).toBeVisible({ timeout: 60_000 });
+    // Visible can come before the stream is attached.
+    let trackId: string | undefined;
+    await expect
+      .poll(async () => {
+        trackId = await guestTile
+          .locator("video")
+          .evaluate(
+            (video: HTMLVideoElement) =>
+              (video.srcObject as MediaStream | null)?.getVideoTracks()[0]?.id,
+          );
+        return trackId;
+      })
+      .toBeDefined();
+    await expectNoFrameOfTheRoom(host, trackId!, 0, camera, picture);
+    // The join adopts the lobby's pipeline, so the model is never fetched again.
+    expect(heldBack).toBe(0);
+
+    await hostContext.close();
+    await guestContext.close();
+  });
+});
+
+test.describe("the first build", () => {
+  test("survives the camera turned off and on while it runs", async ({
+    page,
+  }) => {
+    test.setTimeout(120_000);
+    const failures: string[] = [];
+    page.on("console", (m) => {
+      if (m.text().includes("Failed to attach video processor"))
+        failures.push(m.text());
+    });
+    await page.goto("/");
+    await SpaHelpers.createCall(page, "Toggling user", "Toggle while building");
+    const preview = page.locator("video").first();
+    const camera = await cameraColour(preview);
+
+    const held = await holdBackTheModel(page);
+    await page.getByRole("button", { name: "Camera", exact: true }).click();
+    const tile = page.getByRole("menuitemradio", { name: "Background 1" });
+    await tile.click();
+    const picture = await averageColour(tile.locator("img"));
+    await page.keyboard.press("Escape");
+    // New preview tracks, each attached while the first is still building.
+    for (let i = 0; i < 2; i++) {
+      await page.getByTestId("incall_videomute").click();
+      await page.getByTestId("incall_videomute").click();
+    }
+
+    await expect
+      .poll(async () => distance(await averageColour(preview), picture), {
+        timeout: 60_000,
+      })
+      .toBeLessThan(distance(camera, picture) / 2);
+    expect(failures).toEqual([]);
+    expect(held()).toBeGreaterThan(0);
+  });
+});
+
+test.describe("turning the camera on with a background chosen", () => {
+  test("publishes no frame of the room when the camera started off", async ({
+    browser,
+  }) => {
+    test.setTimeout(120_000);
+    const { host, guest, close } = await hostAndGuest(browser);
+    const camera = await cameraColour(guest.locator("video").first());
+    await guest.getByTestId("incall_videomute").click();
+    await guest.getByTestId("lobby_joinCall").click();
+
+    const picture = await chooseBackground(guest);
+    const held = await holdBackTheModel(guest);
+    await guest.getByTestId("incall_videomute").click();
+
+    const trackId = await incomingTrackId(host);
+    await expectNoFrameOfTheRoom(host, trackId, 0, camera, picture);
+    expect(held()).toBeGreaterThan(0);
+    await close();
+  });
+
+  test("publishes no frame of the room when the camera was turned off", async ({
+    browser,
+  }) => {
+    test.setTimeout(120_000);
+    const { host, guest, close } = await hostAndGuest(browser);
+    const camera = await cameraColour(guest.locator("video").first());
+    await guest.getByTestId("lobby_joinCall").click();
+    const trackId = await incomingTrackId(host);
+    await expect
+      .poll(async () => (await framesOf(host, trackId)).length, {
+        timeout: 20_000,
+      })
+      .toBeGreaterThan(0);
+    await guest.getByTestId("incall_videomute").click();
+
+    const picture = await chooseBackground(guest);
+    const held = await holdBackTheModel(guest);
+    const before = (await framesOf(host, trackId)).length;
+    await guest.getByTestId("incall_videomute").click();
+
+    await expectNoFrameOfTheRoom(host, trackId, before, camera, picture);
+    expect(held()).toBeGreaterThan(0);
+    await close();
+  });
+});
+
+/** A host in a call, recording what it receives, and a guest in its lobby. */
+async function hostAndGuest(browser: Browser): Promise<{
+  host: Page;
+  guest: Page;
+  close: () => Promise<void>;
+}> {
+  const hostContext = await browser.newContext();
+  const host = await hostContext.newPage();
+  await recordIncomingFrames(host);
+  await host.goto("/");
+  await SpaHelpers.createCall(host, "Host", "Camera with a background", true);
+  await expect(host.getByTestId("incall_videomute")).toBeEnabled({
+    timeout: 10_000,
+  });
+  const inviteLink = await SpaHelpers.getCallInviteLink(host);
+  await host.keyboard.press("Escape");
+
+  const guestContext = await browser.newContext();
+  const guest = await guestContext.newPage();
+  await guest.goto(inviteLink);
+  await guest.getByTestId("joincall_displayName").fill("Guest");
+  await guest.getByTestId("joincall_joincall").click();
+  await expect(guest.locator("video").first()).toBeVisible();
+  return {
+    host,
+    guest,
+    close: async (): Promise<void> => {
+      await hostContext.close();
+      await guestContext.close();
+    },
+  };
+}
+
+/** Chooses the first shipped picture in the call, and answers its colour. */
+async function chooseBackground(guest: Page): Promise<Colour> {
+  // The lobby has a camera button of its own, so wait for the call's.
+  await expect(guest.getByTestId("incall_leave")).toBeVisible({
+    timeout: 30_000,
+  });
+  await expect(guest.getByTestId("incall_videomute")).toBeEnabled({
+    timeout: 10_000,
+  });
+  await guest.getByRole("button", { name: "Camera", exact: true }).click();
+  const tile = guest.getByRole("menuitemradio", { name: "Background 1" });
+  await tile.click();
+  await expect(tile).toHaveAttribute("aria-checked", "true");
+  const picture = await averageColour(tile.locator("img"));
+  await guest.keyboard.press("Escape");
+  return picture;
+}
+
+/** Makes the pipeline's first build as slow as on the slower route. */
+/** Answers how often it held the model back, which a check should see. */
+async function holdBackTheModel(page: Page): Promise<() => number> {
+  let held = 0;
+  // Routing bypasses the cache, so it waits.
+  await page.route("**/*.tflite*", async (route) => {
+    held += 1;
+    await new Promise((resolve) => setTimeout(resolve, 5_000));
+    await route.continue();
+  });
+  return () => held;
+}
+
+/** The id of the guest's camera track, as the host receives it. */
+async function incomingTrackId(host: Page): Promise<string> {
+  const guestTile = host
+    .getByTestId("videoTile")
+    .filter({ has: host.getByTestId("name_tag").getByText("Guest") });
+  await expect(guestTile.locator("video")).toBeVisible({ timeout: 60_000 });
+  // Visible can come before the stream is attached.
+  let trackId: string | undefined;
+  await expect
+    .poll(async () => {
+      trackId = await guestTile
+        .locator("video")
+        .evaluate(
+          (video: HTMLVideoElement) =>
+            (video.srcObject as MediaStream | null)?.getVideoTracks()[0]?.id,
+        );
+      return trackId;
+    })
+    .toBeDefined();
+  return trackId!;
+}
+
+/** Waits for the picture to arrive, then finds no frame of the room since. */
+async function expectNoFrameOfTheRoom(
+  host: Page,
+  trackId: string,
+  since: number,
+  camera: Colour,
+  picture: Colour,
+): Promise<void> {
+  await expect
+    .poll(
+      async () => {
+        const frames = (await framesOf(host, trackId)).slice(since);
+        // A black frame, as a track starts, is nearer the picture than the
+        // camera, but shows neither.
+        return frames.some(
+          (f) =>
+            distance(f, picture) <
+            Math.min(distance(f, camera), distance(f, [0, 0, 0])),
+        );
+      },
+      { timeout: 60_000 },
+    )
+    .toBe(true);
+  const frames = (await framesOf(host, trackId)).slice(since);
+  expect(
+    frames.filter((f) => distance(f, camera) < distance(f, picture)),
+  ).toEqual([]);
+}
+
+/**
+ * Records the mean colour of every frame of every video track the page
+ * receives, from the moment it arrives: a tile may attach it later than its
+ * first frame.
+ */
+async function recordIncomingFrames(page: Page): Promise<void> {
+  await page.addInitScript(() => {
+    const frames: Record<string, [number, number, number][]> = {};
+    (window as unknown as { receivedFrames: typeof frames }).receivedFrames =
+      frames;
+    const record = (track: MediaStreamTrack): void => {
+      if (track.kind !== "video" || frames[track.id]) return;
+      const seen: [number, number, number][] = (frames[track.id] = []);
+      const video = document.createElement("video");
+      video.muted = true;
+      video.srcObject = new MediaStream([track]);
+      const canvas = document.createElement("canvas");
+      canvas.width = canvas.height = 16;
+      const context = canvas.getContext("2d", { willReadFrequently: true })!;
+      const step = (): void => {
+        context.drawImage(video, 0, 0, 16, 16);
+        const { data } = context.getImageData(0, 0, 16, 16);
+        const sum = [0, 0, 0];
+        for (let i = 0; i < data.length; i += 4)
+          for (let c = 0; c < 3; c++) sum[c] += data[i + c];
+        seen.push(sum.map((v) => v / (data.length / 4)) as Colour);
+        video.requestVideoFrameCallback(step);
+      };
+      video.requestVideoFrameCallback(step);
+      void video.play();
+    };
+    const Connection = window.RTCPeerConnection;
+    window.RTCPeerConnection = class extends Connection {
+      public constructor(...args: ConstructorParameters<typeof Connection>) {
+        super(...args);
+        this.addEventListener("track", (e) => record(e.track));
+      }
+    };
+  });
+}
+
+async function framesOf(page: Page, trackId: string): Promise<Colour[]> {
+  return page.evaluate(
+    (id) =>
+      (
+        window as unknown as {
+          receivedFrames: Record<string, [number, number, number][]>;
+        }
+      ).receivedFrames[id] ?? [],
+    trackId,
+  );
 }
@@ -0,0 +1,85 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, type Locator, type Page, test } from "@playwright/test";
+
+import { createUserAndRoom, resizeContainer, startHarness } from "./harness.ts";
+import { averageColour, cameraColour, expectWearing } from "../utils/colour.ts";
+
+// Background effects need WebGL2, and headless Firefox on a CI runner has none,
+// so it rightly offers none of them.
+test.skip(
+  ({ browserName }) => browserName === "firefox",
+  "Background effects need WebGL2, which headless Firefox on CI does not have",
+);
+
+/**
+ * Background effects with Element Call as a component in a host page: the
+ * pipeline's model and WebAssembly have to load from the component's bundle,
+ * and the portalled menu has to be sized against the call, not the window.
+ * Driven from the lobby, which builds the same menu and pipeline.
+ */
+
+// Sign-in, crypto setup and sync happen twice before anything shows.
+test.describe.configure({ timeout: 180_000 });
+
+test("puts a picture on the call's preview", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("effects");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  await resizeContainer(pane.getByTestId("call-container"), {
+    width: 900,
+    height: 480,
+  });
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+  const preview = pane.locator("video").first();
+  const camera = await cameraColour(preview);
+
+  const tile = await openEffect(page, pane, "Background 1");
+  const picture = await averageColour(tile.locator("img"));
+  await tile.click();
+  await expect(tile).toHaveAttribute("aria-checked", "true");
+  await expectWearing(preview, picture, camera);
+});
+
+test("keeps every effect reachable in a small container", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("effectsreach");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const container = pane.getByTestId("call-container");
+  await resizeContainer(container, { width: 400, height: 360 });
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  const last = await openEffect(page, pane, "Background 2");
+  const list = page.locator("[role='menu'] div[role='none']").first();
+  expect((await list.boundingBox())!.height).toBeLessThanOrEqual(
+    (await container.boundingBox())!.height,
+  );
+  await last.scrollIntoViewIfNeeded();
+  await expect(last).toBeInViewport({ ratio: 1 });
+  await last.click();
+  await expect(last).toHaveAttribute("aria-checked", "true");
+});
+
+/** Opens a component's camera menu and returns one of its effects. */
+async function openEffect(
+  page: Page,
+  pane: Locator,
+  name: string,
+): Promise<Locator> {
+  await pane
+    .getByRole("button", { name: "Camera", exact: true })
+    .click({ timeout: 60_000 });
+  // Portalled out of the pane, so found on the page.
+  return page
+    .getByRole("group", { name: "Background effects" })
+    .getByRole("menuitemradio", { name });
+}
@@ -109,15 +109,7 @@ export const widgetTest = test.extend<MyFixtures>({
      await TestHelpers.dismissInviteUnknownUserModal(ewPage1);

      // Accept the invite
-      await TestHelpers.closeReleaseAnnouncement(
-        ewPage2,
-        "Introducing Sections",
-      );
-      await TestHelpers.expandAllSections(ewPage2);
-      await expect(
-        TestHelpers.roomListItem(ewPage2, "Welcome Room"),
-      ).toBeVisible();
-      await TestHelpers.roomListItem(ewPage2, "Welcome Room").click();
+      await TestHelpers.openRoomInvite(ewPage2, "Welcome Room");
      await ewPage2.getByRole("button", { name: "Accept" }).click();
      await expect(
        ewPage2
@@ -125,17 +117,7 @@ export const widgetTest = test.extend<MyFixtures>({
          .getByRole("heading", { name: "Welcome Room" }),
      ).toBeVisible();
    } else if (callType === "dm") {
-      await TestHelpers.closeReleaseAnnouncement(
-        ewPage1,
-        "Introducing Sections",
-      );
-
-      await ewPage1
-        .getByRole("navigation", { name: "Room list" })
-        .getByRole("button", { name: "New", exact: true })
-        .click();
-
-      await ewPage1.getByRole("menuitem", { name: "Start chat" }).click();
+      await TestHelpers.chooseFromRoomListNewMenu(ewPage1, "Start chat");
      await ewPage1.getByRole("textbox", { name: "Search" }).click();
      await ewPage1.getByRole("textbox", { name: "Search" }).fill(whistlerMxId);
      await ewPage1.getByRole("button", { name: "Go" }).click();
@@ -157,12 +139,7 @@ export const widgetTest = test.extend<MyFixtures>({
      ).toBeVisible();

      // Accept the DM invite from brooks
-      await TestHelpers.closeReleaseAnnouncement(
-        ewPage2,
-        "Introducing Sections",
-      );
-      await TestHelpers.expandAllSections(ewPage2);
-      await TestHelpers.roomListItem(ewPage2, brooksDisplayName).click();
+      await TestHelpers.openRoomInvite(ewPage2, brooksDisplayName);
      await ewPage2.getByRole("button", { name: "Start chatting" }).click();
    }

@@ -0,0 +1,55 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, type Locator } from "@playwright/test";
+
+export type Colour = [number, number, number];
+
+/** The camera's colour, once the preview is showing it rather than nothing. */
+export async function cameraColour(preview: Locator): Promise<Colour> {
+  await expect
+    .poll(async () => Math.max(...(await averageColour(preview))))
+    .toBeGreaterThan(40);
+  return averageColour(preview);
+}
+
+/** The mean colour of a video's current frame or an image, drawn small. */
+export async function averageColour(element: Locator): Promise<Colour> {
+  return element.evaluate(
+    async (source: HTMLVideoElement | HTMLImageElement) => {
+      if (source instanceof HTMLImageElement) await source.decode();
+      const canvas = document.createElement("canvas");
+      canvas.width = canvas.height = 32;
+      const context = canvas.getContext("2d")!;
+      context.drawImage(source, 0, 0, 32, 32);
+      const { data } = context.getImageData(0, 0, 32, 32);
+      const sum = [0, 0, 0];
+      for (let i = 0; i < data.length; i += 4)
+        for (let c = 0; c < 3; c++) sum[c] += data[i + c];
+      const pixels = data.length / 4;
+      return sum.map((s) => s / pixels) as Colour;
+    },
+  );
+}
+
+export function distance(a: Colour, b: Colour): number {
+  return Math.hypot(a[0] - b[0], a[1] - b[1], a[2] - b[2]);
+}
+
+/** Waits until a preview shows a picture rather than the camera. */
+export async function expectWearing(
+  preview: Locator,
+  picture: Colour,
+  camera: Colour,
+): Promise<void> {
+  // Long enough for the first effect of a session to be built.
+  await expect
+    .poll(async () => distance(await averageColour(preview), picture), {
+      timeout: 60_000,
+    })
+    .toBeLessThan(distance(camera, picture) / 2);
+}
@@ -0,0 +1,43 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test } from "@playwright/test";
+
+import { widgetTest } from "../fixtures/widget-user.ts";
+import { TestHelpers } from "./test-helpers.ts";
+import { averageColour, cameraColour, expectWearing } from "../utils/colour.ts";
+
+// Background effects need WebGL2, and headless Firefox on a CI runner has none,
+// so it rightly offers none of them.
+test.skip(
+  ({ browserName }) => browserName === "firefox",
+  "Background effects need WebGL2, which headless Firefox on CI does not have",
+);
+
+widgetTest(
+  "puts a picture on the preview inside Element Web",
+  async ({ asWidget }) => {
+    test.slow();
+    const { brooks } = asWidget;
+    await TestHelpers.startCallInCurrentRoom(brooks.page, false);
+    const frame = brooks.page
+      .locator('iframe[title="Element Call"]')
+      .contentFrame();
+    await expect(frame.getByTestId("lobby_joinCall")).toBeVisible();
+    const preview = frame.locator("video").first();
+    const camera = await cameraColour(preview);
+
+    await frame.getByRole("button", { name: "Camera", exact: true }).click();
+    const tile = frame
+      .getByRole("group", { name: "Background effects" })
+      .getByRole("menuitemradio", { name: "Background 1" });
+    const picture = await averageColour(tile.locator("img"));
+    await tile.click();
+    await expect(tile).toHaveAttribute("aria-checked", "true");
+    await expectWearing(preview, picture, camera);
+  },
+);
@@ -157,25 +157,34 @@ export class TestHelpers {
  // Toast can be stacked, and only the top one can be dismiss, so just look at what is on top and
  // dismiss (if part of expected toats)
  public static async dismissStartupToasts(page: Page): Promise<void> {
-    const expectedToasts = [
+    const expectedToasts: {
+      title: string;
+      button: string;
+      confirm?: string;
+    }[] = [
      { title: "Failed to load service worker", button: "OK" },
      { title: "Back up your chats", button: "Not now" },
-      { title: "Turn on key storage", button: "Dismiss" },
+      {
+        title: "Turn on key storage",
+        button: "Dismiss",
+        confirm: "Yes, dismiss",
+      },
+      { title: "Notifications", button: "Dismiss" },
      { title: "Element does not support this browser", button: "Dismiss" },
    ];

    const toast = page.locator(".mx_Toast_toast");
+    const toastTitle = toast.locator(".mx_Toast_title h2");

    // eslint-disable-next-line no-constant-condition
    while (true) {
      try {
        await toast.waitFor({ state: "visible", timeout: 700 });
-        const title = await toast.locator(".mx_Toast_title h2").textContent();
+        const title = await toastTitle.textContent();
+        if (!title) break;

        // Find the matching toast config
-        const toastConfig = expectedToasts.find((t) =>
-          title?.includes(t.title),
-        );
+        const toastConfig = expectedToasts.find((t) => title.includes(t.title));

        if (toastConfig) {
          // Bounded so that a renamed button leaves the toast in place and the
@@ -183,6 +192,16 @@ export class TestHelpers {
          await toast
            .getByRole("button", { name: toastConfig.button })
            .click({ timeout: 5000 });
+          if (toastConfig.confirm) {
+            const dialog = page.getByRole("dialog");
+            await dialog
+              .getByRole("button", { name: toastConfig.confirm })
+              .click({ timeout: 5000 });
+            await expect(dialog).toBeHidden({ timeout: 5000 });
+          }
+          // The same element shows the next toast a moment after the click, so
+          // reading it straight away acts on the dismissed one a second time
+          await expect(toastTitle).not.toHaveText(title, { timeout: 5000 });
        } else {
          // Unknown toast. We don't want to act on unknown toasts
          break;
@@ -194,6 +213,16 @@ export class TestHelpers {
    }
  }

+  /**
+   * Clears what Element Web stacks over the room list after sign-in. The
+   * release announcement is held back while any toast is up, so it is closed
+   * after the toasts, not before.
+   */
+  public static async clearRoomListOverlays(page: Page): Promise<void> {
+    await TestHelpers.dismissStartupToasts(page);
+    await TestHelpers.closeReleaseAnnouncement(page, "Introducing Sections");
+  }
+
  public static async closeReleaseAnnouncement(
    page: Page,
    name: string,
@@ -223,16 +252,7 @@ export class TestHelpers {
    page: Page,
    andInvite: string[] = [],
  ): Promise<void> {
-    await TestHelpers.closeReleaseAnnouncement(page, "Introducing Sections");
-
-    await page
-      .getByRole("navigation", { name: "Room list" })
-      .getByRole("button", { name: "New", exact: true })
-      .click();
-
-    await page.getByRole("menuitem", { name: "New Room" }).click({
-      timeout: 5000,
-    });
+    await TestHelpers.chooseFromRoomListNewMenu(page, "New Room");
    await page.getByRole("textbox", { name: "Name" }).fill(name);
    await page.getByRole("button", { name: "Create room" }).click();
    await expect(page.getByText("You created this room.")).toBeVisible({
@@ -259,6 +279,25 @@ export class TestHelpers {
    }
  }

+  /**
+   * Opens the room list's "New" menu and picks the given item.
+   *
+   * While the sections announcement is anchored to the "New" button, the
+   * button has no menu at all, so the overlays go first. Driven by keyboard,
+   * as a toast arriving afterwards sits over the button and swallows clicks.
+   */
+  public static async chooseFromRoomListNewMenu(
+    page: Page,
+    itemName: string,
+  ): Promise<void> {
+    await TestHelpers.clearRoomListOverlays(page);
+    await page
+      .getByRole("navigation", { name: "Room list" })
+      .getByRole("button", { name: "New", exact: true })
+      .press("Enter");
+    await page.getByRole("menuitem", { name: itemName }).press("Enter");
+  }
+
  /**
   * Accepts a room invite using the room name.
   * Locatest the invite in the room list.
@@ -268,9 +307,7 @@ export class TestHelpers {
    roomName: string,
    page: Page,
  ): Promise<void> {
-    await TestHelpers.closeReleaseAnnouncement(page, "Introducing Sections");
-    await TestHelpers.expandAllSections(page);
-    await TestHelpers.roomListItem(page, roomName).click({ timeout: 10000 });
+    await TestHelpers.openRoomInvite(page, roomName);
    await page.getByRole("button", { name: "Accept" }).click({
      timeout: 5000,
    });
@@ -376,6 +413,29 @@ export class TestHelpers {
    return page.locator(`[aria-label^="Open room ${roomName}"]`);
  }

+  /**
+   * Opens a pending invite from the room list by its room name.
+   *
+   * Element Web collapses the Invites section every time it appears, so it is
+   * expanded here once the invite has arrived.
+   */
+  public static async openRoomInvite(
+    page: Page,
+    roomName: string,
+  ): Promise<void> {
+    const invitesSection = page.getByRole("button", {
+      name: "Toggle Invites section",
+    });
+    await expect(invitesSection).toBeVisible({ timeout: 10000 });
+    // Toasts and the announcement sit over the top of the room list, where
+    // this header is
+    await TestHelpers.clearRoomListOverlays(page);
+    if ((await invitesSection.getAttribute("aria-expanded")) !== "true") {
+      await invitesSection.click();
+    }
+    await TestHelpers.roomListItem(page, roomName).click({ timeout: 10000 });
+  }
+
  /**
   * Switches to a room in the room list by its name.
   * @param page - The EW page
@@ -160,6 +160,9 @@ importers:
      eslint-plugin-storybook:
        specifier: ^10.3.6
        version: 10.6.2(eslint@8.57.1(supports-color@7.2.0))(supports-color@7.2.0)(typescript@5.9.3)
+      fake-indexeddb:
+        specifier: ^6.2.5
+        version: 6.2.5
      fetch-mock:
        specifier: 11.1.5
        version: 11.1.5(node-fetch@2.7.0)
@@ -4048,6 +4051,10 @@ packages:
    resolution: {integrity: sha512-KfYbmpRm0VbLjEvVa9yGwCi9GI34xvi7A/HXYWQO65CSD2u3MczUJSuwXKFIxlGsgBQizV9q5J9NHj4VG0n+pA==}
    engines: {node: '>=12.0.0'}

+  fake-indexeddb@6.2.5:
+    resolution: {integrity: sha512-CGnyrvbhPlWYMngksqrSSUT1BAVP49dZocrHuK0SvtR0D5TMs5wP0o3j7jexDJW01KSadjBp1M/71o/KR3nD1w==}
+    engines: {node: '>=18'}
+
  fast-deep-equal@3.1.3:
    resolution: {integrity: sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==}

@@ -9712,6 +9719,8 @@ snapshots:

  expect-type@1.4.0: {}

+  fake-indexeddb@6.2.5: {}
+
  fast-deep-equal@3.1.3: {}

  fast-glob@3.3.3:
@@ -90,3 +90,42 @@ Please see LICENSE in the repository root for full details.
  text-align: center;
  overflow-wrap: anywhere;
 }
+
+.removable {
+  position: relative;
+  display: flex;
+  min-inline-size: 0;
+}
+
+.removable > .tile {
+  flex: 1;
+}
+
+/* Clear of the target for choosing the tile. */
+.remove {
+  position: absolute;
+  inset-block-start: 0;
+  inset-inline-end: 0;
+  translate: 20% -20%;
+  display: none;
+  align-items: center;
+  justify-content: center;
+  inline-size: 28px;
+  block-size: 28px;
+  border-radius: 50%;
+  background: var(--cpd-color-bg-canvas-default);
+  color: var(--cpd-color-icon-critical-primary);
+  box-shadow: 0 1.2px 2.4px 0 rgb(0 0 0 / 15%);
+  cursor: pointer;
+}
+
+.remove:hover {
+  background: var(--cpd-color-bg-critical-subtle-hovered);
+  box-shadow: 0 0 0 var(--cpd-border-width-1)
+    var(--cpd-color-border-critical-subtle);
+}
+
+.removable:hover .remove,
+.removable:focus-within .remove {
+  display: flex;
+}
@@ -5,14 +5,16 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */

-import { type FC, type ReactElement } from "react";
+import { type FC, type KeyboardEvent, type ReactElement } from "react";
 import { useTranslation } from "react-i18next";
 import { VisuallyHidden } from "@radix-ui/react-visually-hidden";
-import { InlineSpinner, MenuItem } from "@vector-im/compound-web";
+import { InlineSpinner, MenuItem, Tooltip } from "@vector-im/compound-web";
 import {
  BlockIcon,
  BlurIcon,
  CheckCircleSolidIcon,
+  CloseIcon,
+  PlusIcon,
 } from "@vector-im/compound-design-tokens/assets/web/icons";

 import styles from "./BackgroundEffectGrid.module.css";
@@ -27,6 +29,8 @@ export interface BackgroundEffectGridItem {
  kind: "none" | "blur" | "image";
  /** For kind "image". */
  imageUrl?: string;
+  /** Whether it is the user's to remove. */
+  removable?: boolean;
 }

 interface Props {
@@ -38,6 +42,12 @@ interface Props {
  settling?: boolean;
  /** Id of the text saying what the user should know before choosing. */
  describedBy?: string;
+  /** Offers to add a background of one's own. Omit to leave that tile out. */
+  onAdd?: () => void;
+  addLabel?: string;
+  /** Removes a removable one, never the one in force. Omit to offer none. */
+  onRemove?: (id: string) => void;
+  removeLabel?: string;
 }

 /**
@@ -51,6 +61,10 @@ export const BackgroundEffectGrid: FC<Props> = ({
  onSelect,
  settling = false,
  describedBy,
+  onAdd,
+  addLabel,
+  onRemove,
+  removeLabel,
 }) => {
  const { t } = useTranslation();
  const choose = (id: string): void => {
@@ -66,7 +80,30 @@ export const BackgroundEffectGrid: FC<Props> = ({
          : t("background_effects.numbered", { n: ++pictures });
    const checked = effect.id === selected;
    const disabled = onSelect === undefined && effect.kind !== "none";
-    return (
+    const remove =
+      effect.removable && !checked && onRemove !== undefined
+        ? (): void => onRemove(effect.id)
+        : undefined;
+    const removeProps =
+      remove === undefined
+        ? {}
+        : {
+            "aria-keyshortcuts": "Delete",
+            onKeyDown: (e: KeyboardEvent): void => {
+              if (e.key !== "Delete" && e.key !== "Backspace") return;
+              e.preventDefault();
+              remove();
+            },
+          };
+    const content = (
+      <TileContent
+        effect={effect}
+        label={label}
+        checked={checked}
+        settling={checked && settling}
+      />
+    );
+    const tile = (
      <MenuItem
        key={effect.id}
        role="menuitemradio"
@@ -88,21 +125,57 @@ export const BackgroundEffectGrid: FC<Props> = ({
                choose(effect.id);
              }
        }
+        {...removeProps}
      >
-        <TileContent
-          effect={effect}
-          label={label}
-          checked={checked}
-          settling={checked && settling}
-        />
+        {content}
      </MenuItem>
    );
+    if (remove === undefined) return tile;
+    // Beside the item, not in it: inside, the item takes the press first and
+    // the tile is chosen instead.
+    return (
+      <div key={effect.id} className={styles.removable}>
+        {tile}
+        <Tooltip label={removeLabel ?? ""}>
+          {/* Not a control of its own, so the menu keeps one keyboard model:
+              the keyboard reaches the same action through Delete. */}
+          <span aria-hidden className={styles.remove} onClick={remove}>
+            <CloseIcon width={20} height={20} />
+          </span>
+        </Tooltip>
+      </div>
+    );
  });

+  // A command rather than a choice, so an item beside the radios.
+  const addContent = (
+    <>
+      <span aria-hidden className={styles.swatch}>
+        <PlusIcon width={24} height={24} />
+      </span>
+      <VisuallyHidden>{addLabel}</VisuallyHidden>
+    </>
+  );
+  const addTile =
+    onAdd === undefined ? null : (
+      <MenuItem
+        label={null}
+        hideChevron
+        className={styles.tile}
+        onSelect={(e) => {
+          e.preventDefault();
+          onAdd();
+        }}
+      >
+        {addContent}
+      </MenuItem>
+    );
+
  return (
    // A group of its own, as the section's can't carry the description.
    <div role="group" aria-describedby={describedBy} className={styles.grid}>
      {tiles}
+      {addTile}
    </div>
  );
 };
@@ -127,16 +127,20 @@ export const Default: Story = {
    selectBackgroundEffect: fn(),
    backgroundEffect: "blur",
    backgroundEffects: [
-      { id: "none", kind: "none" },
-      { id: "blur", kind: "blur" },
+      { id: "none", kind: "none", removable: false },
+      { id: "blur", kind: "blur", removable: false },
      ...shippedBackgrounds.map((background) => ({
        id: `image:${background.id}`,
        kind: "image" as const,
        imageUrl: background.imagePath,
+        removable: false,
      })),
    ],
    backgroundEffectNotice: undefined,
    backgroundEffectSettling: false,
+    backgroundImageRefusal: undefined,
+    addBackgroundImage: fn(),
+    removeBackgroundEffect: fn(),
    hangup: fn(),
    buttonSize: "lg",
    showFooter: true,
@@ -33,6 +33,11 @@ import { useBehavior } from "../useBehavior";
 import { type LayoutSwitchViewModel } from "../state/LayoutSwitchViewModel";
 import { LayoutSwitch } from "../room/LayoutSwitch";
 import { type BackgroundEffectGridItem } from "./BackgroundEffectGrid";
+import { type UnusableReason } from "../tracks/backgroundImages";
+
+export interface BackgroundImageRefusal {
+  reason: UnusableReason | "not-kept";
+}

 export interface AudioOutputSwitcher {
  targetOutput: string;
@@ -60,6 +65,10 @@ export interface FooterActions {
  toggleVideo: (() => void) | undefined;
  /** Undefined where background effects can't be chosen. */
  selectBackgroundEffect: ((id: string) => void) | undefined;
+  /** Undefined where no background can be added. */
+  addBackgroundImage: ((file: File) => void) | undefined;
+  /** Removes an added background by its option id; never the one in force. */
+  removeBackgroundEffect: ((id: string) => void) | undefined;
  toggleScreenSharing: (() => void) | undefined;
  /** Also controls if the settings button is visible */
  openSettings: (() => void) | undefined;
@@ -81,6 +90,8 @@ export interface FooterState {
  backgroundEffectNotice: "unavailable" | "slow" | undefined;
  /** Whether the first effect chosen is still being prepared. */
  backgroundEffectSettling: boolean;
+  /** Why the last file offered couldn't be kept, if it couldn't. */
+  backgroundImageRefusal: BackgroundImageRefusal | undefined;
  showFooter: boolean;

  /* This is needed for WindowMode = "flat" */
@@ -168,6 +179,23 @@ export const CallFooter: FC<FooterProps> = ({
  const selectBackgroundEffect = useBehavior(vm.selectBackgroundEffect$);
  const backgroundEffectNotice = useBehavior(vm.backgroundEffectNotice$);
  const backgroundEffectSettling = useBehavior(vm.backgroundEffectSettling$);
+  const addBackgroundImage = useBehavior(vm.addBackgroundImage$);
+  const removeBackgroundEffect = useBehavior(vm.removeBackgroundEffect$);
+  const refusal = useBehavior(vm.backgroundImageRefusal$);
+  const refusalMessage = useMemo(() => {
+    switch (refusal?.reason) {
+      case undefined:
+        return undefined;
+      case "not-an-image":
+        return { text: t("error.background_not_an_image") };
+      case "animated":
+        return { text: t("error.background_animated") };
+      case "undecodable":
+        return { text: t("error.background_undecodable") };
+      case "not-kept":
+        return { text: t("error.background_not_kept") };
+    }
+  }, [refusal, t]);
  const backgroundEffects = useBehavior(vm.backgroundEffects$);
  const buttonSize = useBehavior(vm.buttonSize$);
  const showLogo = useBehavior(vm.showLogo$);
@@ -234,6 +262,9 @@ export const CallFooter: FC<FooterProps> = ({
        selectedBackgroundEffect={backgroundEffect}
        onSelectBackgroundEffect={selectBackgroundEffect}
        backgroundEffectSettling={backgroundEffectSettling}
+        onAddBackgroundImage={addBackgroundImage}
+        onRemoveBackgroundEffect={removeBackgroundEffect}
+        backgroundImageRefusal={refusalMessage}
        backgroundEffectNotice={
          backgroundEffectNotice === "unavailable"
            ? t("background_effects.unavailable")
@@ -8,7 +8,12 @@ Please see LICENSE in the repository root for full details.
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { BehaviorSubject } from "rxjs";

-import { testScope, mockMuteStates, mockMediaDevices } from "../utils/test";
+import {
+  flushPromises,
+  testScope,
+  mockMuteStates,
+  mockMediaDevices,
+} from "../utils/test";
 import { constant } from "../state/Behavior";
 import type { CallViewModel } from "../state/CallViewModel/CallViewModel";
 import type { Layout } from "../state/layout-types";
@@ -21,6 +26,13 @@ import {
 import { HeaderStyle } from "../UrlParams";
 import { backgroundEffect as backgroundEffectSetting } from "../settings/settings";
 import { shippedBackgrounds } from "../tracks/backgroundEffectCatalog";
+import type * as BackgroundImages from "../tracks/backgroundImages";
+import {
+  type AddedBackground,
+  addedBackgrounds,
+  maxAddedBackgrounds,
+  UnusableImage,
+} from "../tracks/backgroundImages";

 const platformMock = vi.hoisted(() => vi.fn(() => "desktop"));
 vi.mock("../Platform", () => ({
@@ -37,6 +49,22 @@ vi.mock("@livekit/track-processors", () => ({
  supportsModernBackgroundProcessors: (): boolean => modernRouteMock(),
 }));

+const store = vi.hoisted(() => ({
+  add: vi.fn<(file: Blob) => Promise<string>>(),
+  remove: vi.fn<(id: string) => Promise<void>>(),
+}));
+vi.mock("../tracks/backgroundImages", async (original) => {
+  const { BehaviorSubject } = await import("rxjs");
+  return {
+    ...(await original<typeof BackgroundImages>()),
+    addedBackgrounds: {
+      added$: new BehaviorSubject<AddedBackground[] | undefined>([]),
+      add: store.add,
+      remove: store.remove,
+    },
+  };
+});
+
 const outputSelectionMock = vi.hoisted(() => vi.fn(() => true));
 vi.mock("livekit-client", () => ({
  supportsAudioOutputSelection: (): boolean => outputSelectionMock(),
@@ -263,6 +291,7 @@ describe("createCallFooterViewModel", () => {
    it("offers nothing where the browser itself cannot run them", () => {
      sdkSupportMock.mockReturnValue(false);
      expect(lobbyOn("desktop").selectBackgroundEffect$.value).toBeUndefined();
+      expect(lobbyOn("desktop").addBackgroundImage$.value).toBeUndefined();
    });

    it("puts no effect in force where the browser cannot run them", () => {
@@ -293,17 +322,29 @@ describe("createCallFooterViewModel", () => {
      expect(lobbyOn("desktop").backgroundEffectNotice$.value).toBeUndefined();
    });

-    it("offers every effect in order", () => {
+    it("offers every effect in order, the added ones removable", () => {
      sdkSupportMock.mockReturnValue(true);
+      const added$ = addedBackgrounds.added$ as BehaviorSubject<
+        AddedBackground[] | undefined
+      >;
+      added$.next([{ id: "mine", url: "blob:mine" }]);
      expect(lobbyOn("desktop").backgroundEffects$.value).toEqual([
-        { id: "none", kind: "none" },
-        { id: "blur", kind: "blur" },
+        { id: "none", kind: "none", removable: false },
+        { id: "blur", kind: "blur", removable: false },
        ...shippedBackgrounds.map((background) => ({
          id: `image:${background.id}`,
          kind: "image",
          imageUrl: background.imagePath,
+          removable: false,
        })),
+        {
+          id: "added:mine",
+          kind: "image",
+          imageUrl: "blob:mine",
+          removable: true,
+        },
      ]);
+      added$.next([]);
    });

    it("says they are unavailable where they cannot be chosen", () => {
@@ -330,6 +371,62 @@ describe("createCallFooterViewModel", () => {
      expect(vm.backgroundEffectSettling$.value).toBe(false);
    });

+    it("adding is unavailable at the limit", () => {
+      sdkSupportMock.mockReturnValue(true);
+      const added$ = addedBackgrounds.added$ as BehaviorSubject<
+        AddedBackground[] | undefined
+      >;
+      const vm = lobbyOn("desktop");
+      expect(vm.addBackgroundImage$.value).toBeDefined();
+      added$.next(
+        Array.from({ length: maxAddedBackgrounds }, (_, i) => ({
+          id: `${i}`,
+          url: `blob:${i}`,
+        })),
+      );
+      expect(vm.addBackgroundImage$.value).toBeUndefined();
+      added$.next(added$.value!.slice(1));
+      expect(vm.addBackgroundImage$.value).toBeDefined();
+      added$.next([]);
+    });
+
+    it("says why each refused file was refused", async () => {
+      sdkSupportMock.mockReturnValue(true);
+      const vm = lobbyOn("desktop");
+      store.add.mockRejectedValue(new UnusableImage("animated"));
+      vm.addBackgroundImage$.value!(new File(["x"], "a.gif"));
+      await flushPromises();
+      const first = vm.backgroundImageRefusal$.value;
+      expect(first).toEqual({ reason: "animated" });
+
+      // The same again is a refusal of its own, so it is shown again.
+      vm.addBackgroundImage$.value!(new File(["x"], "a.gif"));
+      await flushPromises();
+      expect(vm.backgroundImageRefusal$.value).toEqual({ reason: "animated" });
+      expect(vm.backgroundImageRefusal$.value).not.toBe(first);
+
+      store.add.mockRejectedValue(new Error("quota"));
+      vm.addBackgroundImage$.value!(new File(["x"], "b.png"));
+      await flushPromises();
+      expect(vm.backgroundImageRefusal$.value).toEqual({ reason: "not-kept" });
+
+      store.add.mockResolvedValue("kept");
+      vm.addBackgroundImage$.value!(new File(["x"], "c.png"));
+      await flushPromises();
+      expect(vm.backgroundImageRefusal$.value).toBeUndefined();
+    });
+
+    it("never removes the background in force", () => {
+      sdkSupportMock.mockReturnValue(true);
+      store.remove.mockResolvedValue();
+      const vm = lobbyOn("desktop");
+      backgroundEffectSetting.setValue("added:worn");
+      vm.removeBackgroundEffect$.value!("added:worn");
+      expect(store.remove).not.toHaveBeenCalled();
+      vm.removeBackgroundEffect$.value!("added:spare");
+      expect(store.remove).toHaveBeenCalledWith("spare");
+    });
+
    it("availability is the same before and during a call", () => {
      for (const supported of [true, false]) {
        sdkSupportMock.mockReturnValue(supported);
@@ -6,6 +6,7 @@ Please see LICENSE in the repository root for full details.
 */

 import {
+  BehaviorSubject,
  combineLatest,
  distinctUntilChanged,
  map,
@@ -17,12 +18,19 @@ import {
  supportsBackgroundProcessors,
  supportsModernBackgroundProcessors,
 } from "@livekit/track-processors";
+import { logger } from "matrix-js-sdk/lib/logger";

 import {
  parseEffect,
  serializeEffect,
  shippedBackgrounds,
 } from "../tracks/backgroundEffectCatalog";
+import {
+  type AddedBackground,
+  addedBackgrounds,
+  maxAddedBackgrounds,
+  UnusableImage,
+} from "../tracks/backgroundImages";

 import { type CallViewModel } from "../state/CallViewModel/CallViewModel";
 import { type MenuOptions } from "./MediaMuteAndSwitchButton";
@@ -37,7 +45,7 @@ import { type MuteStates } from "../state/MuteStates";
 import { createStaticViewModel, type ViewModel } from "../state/ViewModel";
 import { HeaderStyle } from "../UrlParams";
 import { platform } from "../Platform";
-import { type FooterSnapshot } from "./CallFooter";
+import { type BackgroundImageRefusal, type FooterSnapshot } from "./CallFooter";
 import { type BackgroundEffectGridItem } from "./BackgroundEffectGrid";

 /**
@@ -96,6 +104,9 @@ function buildDeviceBehaviors(
  | "backgroundEffects$"
  | "backgroundEffectNotice$"
  | "backgroundEffectSettling$"
+  | "addBackgroundImage$"
+  | "backgroundImageRefusal$"
+  | "removeBackgroundEffect$"
 > {
  const options$ = (
    available$: Behavior<Map<string, MenuOptions["label"]>>,
@@ -117,6 +128,10 @@ function buildDeviceBehaviors(
  const offered$ = disableSwitcher$.pipe(
    map((switcherDisabled) => !switcherDisabled && supported),
  );
+  // A new object for each refusal, so the same one twice is shown twice.
+  const refusal$ = new BehaviorSubject<BackgroundImageRefusal | undefined>(
+    undefined,
+  );
  return {
    audioOptions$: scope.behavior(options$(mediaDevices.audioInput.available$)),
    selectedAudio$: scope.behavior(
@@ -158,7 +173,11 @@ function buildDeviceBehaviors(
        ),
      ),
    ),
-    backgroundEffects$: constant(backgroundEffectChoices()),
+    backgroundEffects$: scope.behavior(
+      addedBackgrounds.added$.pipe(
+        map((added) => backgroundEffectChoices(added ?? [])),
+      ),
+    ),
    backgroundEffectNotice$: scope.behavior(
      offered$.pipe(
        map((offered) =>
@@ -170,6 +189,44 @@ function buildDeviceBehaviors(
      backgroundEffectSettling$.pipe(distinctUntilChanged()),
      false,
    ),
+    // Kept and offered, not put on: that waits for the user to choose it.
+    addBackgroundImage$: scope.behavior(
+      combineLatest([offered$, addedBackgrounds.added$]).pipe(
+        map(([offered, added]) =>
+          offered && (added?.length ?? 0) < maxAddedBackgrounds
+            ? (file: File): void => {
+                refusal$.next(undefined);
+                addedBackgrounds.add(file).catch((e) => {
+                  logger.warn("Could not keep that background", e);
+                  refusal$.next({
+                    reason: e instanceof UnusableImage ? e.reason : "not-kept",
+                  });
+                });
+              }
+            : undefined,
+        ),
+      ),
+    ),
+    backgroundImageRefusal$: refusal$,
+    // Never the one in force: taking it away would leave nothing chosen.
+    removeBackgroundEffect$: scope.behavior(
+      offered$.pipe(
+        map((offered) =>
+          offered
+            ? (optionId: string): void => {
+                const effect = parseEffect(optionId);
+                if (effect.kind !== "added") return;
+                if (backgroundEffectSetting.getValue() === optionId) return;
+                addedBackgrounds
+                  .remove(effect.id)
+                  .catch((e) =>
+                    logger.warn("Could not remove that background", e),
+                  );
+              }
+            : undefined,
+        ),
+      ),
+    ),
  };
 }

@@ -337,14 +394,23 @@ export function createLobbyFooterViewModel(
  };
 }

-function backgroundEffectChoices(): BackgroundEffectGridItem[] {
+function backgroundEffectChoices(
+  added: AddedBackground[],
+): BackgroundEffectGridItem[] {
  return [
-    { id: serializeEffect({ kind: "none" }), kind: "none" },
-    { id: serializeEffect({ kind: "blur" }), kind: "blur" },
+    { id: serializeEffect({ kind: "none" }), kind: "none", removable: false },
+    { id: serializeEffect({ kind: "blur" }), kind: "blur", removable: false },
    ...shippedBackgrounds.map((background) => ({
      id: serializeEffect({ kind: "shipped", id: background.id }),
      kind: "image" as const,
      imageUrl: background.imagePath,
+      removable: false,
+    })),
+    ...added.map((background) => ({
+      id: serializeEffect({ kind: "added", id: background.id }),
+      kind: "image" as const,
+      imageUrl: background.url,
+      removable: true,
    })),
  ];
 }
@@ -93,3 +93,7 @@ Please see LICENSE in the repository root for full details.
  flex-shrink: 0;
  color: var(--cpd-color-icon-secondary);
 }
+
+.refusal {
+  margin: var(--cpd-space-2x) var(--cpd-space-4x) 0;
+}
@@ -198,6 +198,7 @@ export const VideoUnmute: Story = {
    backgroundEffects: effects,
    selectedBackgroundEffect: "none",
    onSelectBackgroundEffect: fn(),
+    onAddBackgroundImage: fn(),
  },
 };

@@ -241,6 +242,11 @@ export const BackgroundEffects: Story = {
        true,
      );

+    const add = within(section).getByRole("menuitem", { name: "Add image" });
+    await expect(
+      tiles[3].compareDocumentPosition(add) & Node.DOCUMENT_POSITION_FOLLOWING,
+    ).toBeTruthy();
+
    await userEvent.click(menu.getByRole("menuitemradio", { name: "Blur" }));
    await expect(args.onSelectBackgroundEffect).toHaveBeenCalledWith("blur");
    await expect(menu.getByRole("menu")).toBeVisible();
@@ -341,6 +347,160 @@ export const BackgroundEffectsSettling: Story = {
  },
 };

+/** A file that can't be used: said where it was chosen, and nothing changes. */
+export const BackgroundImageRefused: Story = {
+  args: {
+    ...VideoUnmute.args,
+    selectedBackgroundEffect: "blur",
+    backgroundEffectNotice:
+      "Background effects run slowly on this platform, which may cause your video to stutter.",
+    backgroundImageRefusal: { text: "That file is not a supported image" },
+  },
+  decorators: [
+    (Story): JSX.Element => (
+      <WithACallArea blockSize={300}>
+        <Story />
+      </WithACallArea>
+    ),
+  ],
+  play: async ({ canvasElement }) => {
+    const canvas = within(canvasElement);
+    await userEvent.click(canvas.getByRole("button", { name: "Camera" }));
+    const menu = within(document.body);
+    const message = await menu.findByText("That file is not a supported image");
+    const list = document.body.querySelector<HTMLElement>(
+      `.${styles.deviceList}`,
+    )!;
+    await expect(list.scrollHeight).toBeGreaterThan(list.clientHeight);
+    const scrollport = list.getBoundingClientRect();
+    const shown = message.getBoundingClientRect();
+    await expect(shown.bottom).toBeLessThanOrEqual(scrollport.bottom + 1);
+    await expect(shown.top).toBeGreaterThanOrEqual(scrollport.top - 1);
+    await expect(menu.queryByText(/run slowly/)).toBeNull();
+    await expect(
+      menu.getByRole("menuitemradio", { name: "Blur" }),
+    ).toHaveAttribute("aria-checked", "true");
+  },
+};
+
+/** A flat picture, for backgrounds of one's own. */
+function swatch(colour: string): string {
+  return `data:image/svg+xml,${encodeURIComponent(
+    `<svg xmlns="http://www.w3.org/2000/svg" width="16" height="9"><rect width="16" height="9" fill="${colour}"/></svg>`,
+  )}`;
+}
+
+/** One's own backgrounds are removable, never the one in force. */
+export const AddedBackgroundsCanBeRemoved: Story = {
+  args: {
+    ...VideoUnmute.args,
+    backgroundEffects: [
+      ...effects,
+      {
+        id: "added:one",
+        kind: "image",
+        imageUrl: swatch("#c2410c"),
+        removable: true,
+      },
+      {
+        id: "added:two",
+        kind: "image",
+        imageUrl: swatch("#1d4ed8"),
+        removable: true,
+      },
+    ],
+    selectedBackgroundEffect: "added:one",
+    onRemoveBackgroundEffect: fn(),
+  },
+  play: async ({ args, canvasElement }) => {
+    const canvas = within(canvasElement);
+    await userEvent.click(canvas.getByRole("button", { name: "Camera" }));
+    const body = within(document.body);
+
+    const inForce = await body.findByRole("menuitemradio", {
+      name: "Background 3",
+    });
+    await expect(inForce).not.toHaveAttribute("aria-keyshortcuts");
+
+    const other = body.getByRole("menuitemradio", { name: "Background 4" });
+    await expect(other).toHaveAttribute("aria-keyshortcuts", "Delete");
+    other.focus();
+    await userEvent.keyboard("{Delete}");
+    await expect(args.onRemoveBackgroundEffect).toHaveBeenCalledWith(
+      "added:two",
+    );
+
+    const wrapper = other.parentElement!;
+    await userEvent.hover(wrapper);
+    const cross = wrapper.querySelector<HTMLElement>(
+      "[aria-hidden]:last-child",
+    )!;
+    const probe = document.createElement("span");
+    probe.style.color = "var(--cpd-color-icon-critical-primary)";
+    cross.append(probe);
+    const critical = getComputedStyle(probe).color;
+    probe.remove();
+    await expect(getComputedStyle(cross).color).toBe(critical);
+    const tile = other.getBoundingClientRect();
+    const box = cross.getBoundingClientRect();
+    await expect(box.right).toBeGreaterThan(tile.right);
+    await expect(box.top).toBeLessThan(tile.top);
+
+    await userEvent.hover(cross);
+    await waitFor(async () =>
+      expect(
+        [...document.body.querySelectorAll("div")].some(
+          (d) => d.textContent === "Remove" && d.offsetParent !== null,
+        ),
+      ).toBe(true),
+    );
+  },
+};
+
+/** Removing by pointer while the selection really changes. */
+export const RemovingWithLiveSelection: Story = {
+  args: AddedBackgroundsCanBeRemoved.args,
+  render: function WithLiveSelection(args): JSX.Element {
+    const [selected, setSelected] = useState("none");
+    const [offered, setOffered] = useState(args.backgroundEffects ?? []);
+    return (
+      <MediaMuteAndSwitchButton
+        {...args}
+        backgroundEffects={offered}
+        selectedBackgroundEffect={selected}
+        onSelectBackgroundEffect={setSelected}
+        onRemoveBackgroundEffect={(id): void =>
+          setOffered((current) => current.filter((o) => o.id !== id))
+        }
+      />
+    );
+  },
+  play: async ({ canvasElement }) => {
+    const canvas = within(canvasElement);
+    await userEvent.click(canvas.getByRole("button", { name: "Camera" }));
+    const body = within(document.body);
+
+    const tile = await body.findByRole("menuitemradio", {
+      name: "Background 4",
+    });
+    await userEvent.hover(tile);
+    const cross = tile.parentElement!.querySelector<HTMLElement>(
+      "[aria-hidden]:last-child",
+    )!;
+    await expect(cross).toBeVisible();
+    await userEvent.click(cross);
+
+    await waitFor(async () =>
+      expect(
+        body.queryByRole("menuitemradio", { name: "Background 4" }),
+      ).toBeNull(),
+    );
+    await expect(
+      body.getByRole("menuitemradio", { name: "None" }),
+    ).toHaveAttribute("aria-checked", "true");
+  },
+};
+
 /** In a short call the effects scroll into view with the list. */
 export const BackgroundEffectsScrollWhenTheyDoNotFit: Story = {
  args: {
@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */

-import { afterEach, describe, expect, test, vi } from "vitest";
+import { afterEach, describe, expect, onTestFinished, test, vi } from "vitest";
 import { axe } from "vitest-axe";
 import {
  act,
@@ -367,6 +367,120 @@ describe("MediaMuteAndSwitchButton", () => {
    expect(onSelectBackgroundEffect).not.toHaveBeenCalled();
  });

+  test("added images are chosen like shipped ones", async () => {
+    const user = userEvent.setup();
+    const onSelectBackgroundEffect = vi.fn();
+    const { getByRole } = renderComponent(
+      <MediaMuteAndSwitchButton
+        iconsAndLabels="video"
+        enabled={true}
+        options={[{ label: { type: "name", name: "Camera 1" }, id: "cam1" }]}
+        selectedOption="cam1"
+        backgroundEffects={[
+          ...effects,
+          {
+            id: "added:mine",
+            kind: "image",
+            imageUrl: "",
+          },
+        ]}
+        selectedBackgroundEffect="none"
+        onSelectBackgroundEffect={onSelectBackgroundEffect}
+      />,
+    );
+
+    await user.click(getByRole("button", { name: "Camera" }));
+    const section = screen.getByRole("group", { name: "Background effects" });
+    await user.click(
+      within(section).getByRole("menuitemradio", { name: "Background 3" }),
+    );
+    expect(onSelectBackgroundEffect).toHaveBeenCalledWith("added:mine");
+  });
+
+  test("adds the file chosen from the add tile, and stays open", async () => {
+    const user = userEvent.setup();
+    const onAddBackgroundImage = vi.fn();
+    const pick = vi
+      .spyOn(HTMLInputElement.prototype, "click")
+      .mockImplementation(() => {});
+    try {
+      const { getByRole, container } = renderComponent(
+        <MediaMuteAndSwitchButton
+          iconsAndLabels="video"
+          enabled={true}
+          options={[{ label: { type: "name", name: "Camera 1" }, id: "cam1" }]}
+          selectedOption="cam1"
+          backgroundEffects={effects}
+          selectedBackgroundEffect="none"
+          onSelectBackgroundEffect={vi.fn()}
+          onAddBackgroundImage={onAddBackgroundImage}
+        />,
+      );
+
+      await user.click(getByRole("button", { name: "Camera" }));
+      await user.click(screen.getByRole("menuitem", { name: "Add image" }));
+      expect(pick).toHaveBeenCalled();
+      // The picker takes the focus, which would otherwise close the menu.
+      await user.keyboard("{Escape}");
+      expect(screen.getByRole("menu")).toBeInTheDocument();
+
+      const file = new File(["x"], "mine.png", { type: "image/png" });
+      // What the picker hands back; the open menu blocks pointer events.
+      fireEvent.change(
+        container.querySelector<HTMLInputElement>("input[type=file]")!,
+        { target: { files: [file] } },
+      );
+      expect(onAddBackgroundImage).toHaveBeenCalledWith(file);
+      screen.getByRole("menuitemradio", { name: "None", checked: true });
+    } finally {
+      pick.mockRestore();
+    }
+  });
+
+  test("a refusal can be dismissed and does not outlive the menu", async () => {
+    const user = userEvent.setup();
+    // jsdom lays nothing out, so has nothing to scroll.
+    const scroll = Element.prototype.scrollIntoView;
+    Element.prototype.scrollIntoView = vi.fn();
+    onTestFinished(() => {
+      Element.prototype.scrollIntoView = scroll;
+    });
+    const menu = (refusal?: { text: string }): JSX.Element =>
+      withProviders(
+        <MediaMuteAndSwitchButton
+          iconsAndLabels="video"
+          enabled={true}
+          options={[{ label: { type: "name", name: "Camera 1" }, id: "cam1" }]}
+          selectedOption="cam1"
+          backgroundEffects={effects}
+          selectedBackgroundEffect="blur"
+          onSelectBackgroundEffect={vi.fn()}
+          onAddBackgroundImage={vi.fn()}
+          backgroundImageRefusal={refusal}
+        />,
+      );
+    const { rerender, getByRole } = render(menu());
+    await user.click(getByRole("button", { name: "Camera" }));
+
+    rerender(menu({ text: "That file is not a supported image" }));
+    expect(
+      screen.getByText("That file is not a supported image"),
+    ).toBeVisible();
+    screen.getByRole("menuitemradio", { name: "Blur", checked: true });
+    await user.click(screen.getByRole("button", { name: "Close" }));
+    expect(screen.queryByText("That file is not a supported image")).toBeNull();
+
+    // The next refusal is shown, even if it says the same.
+    rerender(menu({ text: "That file is not a supported image" }));
+    expect(
+      screen.getByText("That file is not a supported image"),
+    ).toBeVisible();
+
+    await user.keyboard("{Escape}");
+    await user.click(getByRole("button", { name: "Camera" }));
+    expect(screen.queryByText("That file is not a supported image")).toBeNull();
+  });
+
  test("offers the background effects in a phone's drawer", async () => {
    const userAgent = vi
      .spyOn(navigator, "userAgent", "get")
@@ -8,6 +8,7 @@ Please see LICENSE in the repository root for full details.
 import {
  useCallback,
  useId,
+  useRef,
  useState,
  type CSSProperties,
  type FC,
@@ -15,6 +16,7 @@ import {
  type ReactElement,
 } from "react";
 import {
+  Alert,
  Button,
  Menu,
  MenuItem,
@@ -79,6 +81,12 @@ export interface MediaMuteAndSwitchButtonProps {
  backgroundEffectNotice?: string;
  /** Whether the first effect chosen is still being prepared. */
  backgroundEffectSettling?: boolean;
+  /** Called with the file chosen from the add tile. Omit to leave it out. */
+  onAddBackgroundImage?: (file: File) => void;
+  /** Removes a removable effect, never the one in force. */
+  onRemoveBackgroundEffect?: (id: string) => void;
+  /** Why the last file offered couldn't be used; a new object each time. */
+  backgroundImageRefusal?: { text: string };
  /**
   * For any toggle and option this method will be called.
   * So toggles need to be implemented by listening here and setting the right toggle item to `enabled`
@@ -113,6 +121,9 @@ export const MediaMuteAndSwitchButton: FC<MediaMuteAndSwitchButtonProps> = ({
  onSelectBackgroundEffect,
  backgroundEffectNotice,
  backgroundEffectSettling,
+  onAddBackgroundImage,
+  onRemoveBackgroundEffect,
+  backgroundImageRefusal,
  onSelect,
 }) => {
  // Requested but not yet selected. Keyed by kind too, since Chrome uses
@@ -122,11 +133,42 @@ export const MediaMuteAndSwitchButton: FC<MediaMuteAndSwitchButtonProps> = ({
    id: string;
  } | null>(null);
  const [menuOpen, setMenuOpen] = useState(false);
-  const onOpenChange = useCallback((open: boolean): void => {
-    setMenuOpen(open);
-    // Drop a request that never arrived.
-    if (!open) setPlannedSelection(null);
+  // The file picker takes the focus, which the menu reads as a click
+  // elsewhere; it is held open until the picker is done.
+  const choosingFile = useRef(false);
+  const fileInput = useRef<HTMLInputElement | null>(null);
+  // A refusal is about the attempt that caused it: shown until dismissed or
+  // until the menu closes, and again for the next one.
+  const [seenRefusal, setSeenRefusal] = useState<object>();
+  const refusal =
+    backgroundImageRefusal !== seenRefusal ? backgroundImageRefusal : undefined;
+  const onOpenChange = useCallback(
+    (open: boolean): void => {
+      if (!open && choosingFile.current) return;
+      setMenuOpen(open);
+      // Drop a request that never arrived.
+      if (!open) setPlannedSelection(null);
+      if (!open) setSeenRefusal(backgroundImageRefusal);
+    },
+    [backgroundImageRefusal],
+  );
+  // Scrolled to as it appears, as the list may be scrolled away from it.
+  const scrollIntoView = useCallback((element: HTMLElement | null): void => {
+    element?.scrollIntoView({ block: "nearest" });
  }, []);
+  const watchFileInput = useCallback(
+    (input: HTMLInputElement | null): (() => void) | undefined => {
+      fileInput.current = input;
+      if (input === null) return;
+      // Dismissing the picker fires cancel, which React doesn't type.
+      const done = (): void => {
+        choosingFile.current = false;
+      };
+      input.addEventListener("cancel", done);
+      return (): void => input.removeEventListener("cancel", done);
+    },
+    [],
+  );
  const isBusy = busy ?? false;
  const { t } = useTranslation();
  const devices = useMediaDevices();
@@ -326,6 +368,21 @@ export const MediaMuteAndSwitchButton: FC<MediaMuteAndSwitchButtonProps> = ({
    >
      {/* The mute button lives inside */}
      {button}
+      {onAddBackgroundImage !== undefined && (
+        <input
+          ref={watchFileInput}
+          type="file"
+          accept="image/*"
+          hidden
+          onChange={(e) => {
+            const file = e.target.files?.[0];
+            // Cleared, so the same file can be chosen twice in a row.
+            e.target.value = "";
+            choosingFile.current = false;
+            if (file) onAddBackgroundImage(file);
+          }}
+        />
+      )}
      <Menu
        className={styles.menu}
        // Named for screen readers only: each section has its own heading.
@@ -394,14 +451,39 @@ export const MediaMuteAndSwitchButton: FC<MediaMuteAndSwitchButtonProps> = ({
                describedBy={
                  backgroundEffectNotice === undefined ? undefined : noticeId
                }
+                onAdd={
+                  onAddBackgroundImage === undefined
+                    ? undefined
+                    : (): void => {
+                        choosingFile.current = true;
+                        fileInput.current?.click();
+                      }
+                }
+                addLabel={t("action.add_background_image")}
+                onRemove={onRemoveBackgroundEffect}
+                removeLabel={t("action.remove")}
              />
              {/* In the list, so the menu grows no taller for it. */}
-              {backgroundEffectNotice !== undefined && (
-                <div id={noticeId} role="none" className={styles.notice}>
-                  <InfoIcon width={20} height={20} />
-                  <span>{backgroundEffectNotice}</span>
+              {refusal !== undefined && (
+                <div
+                  ref={scrollIntoView}
+                  role="none"
+                  className={styles.refusal}
+                >
+                  <Alert
+                    type="critical"
+                    title={refusal.text}
+                    onClose={(): void => setSeenRefusal(refusal)}
+                  />
                </div>
              )}
+              {refusal === undefined &&
+                backgroundEffectNotice !== undefined && (
+                  <div id={noticeId} role="none" className={styles.notice}>
+                    <InfoIcon width={20} height={20} />
+                    <span>{backgroundEffectNotice}</span>
+                  </div>
+                )}
            </MenuScrollSection>
          )}
        </MenuScrollArea>
@@ -15,6 +15,7 @@ import {
  type BackgroundEffectsOptions,
  type BackgroundEffectsState,
 } from "./BackgroundEffects";
+import { type AddedBackground } from "../tracks/backgroundImages";
 import { shippedBackgrounds } from "../tracks/backgroundEffectCatalog";
 import { flushPromises, testScope, withTestScheduler } from "../utils/test";

@@ -69,6 +70,8 @@ describe("the pipeline's state", () => {
      const effects = createBackgroundEffects(testScope(), {
        supported: true,
        effect$: behavior(effect, { n: "none", b: "blur" }),
+        setEffect: vi.fn(),
+        added$: new BehaviorSubject<AddedBackground[] | undefined>([]),
        pipeline: fakePipeline().pipeline,
        transformer,
      });
@@ -94,6 +97,8 @@ describe("the pipeline's state", () => {

 describe("background effects", () => {
  let effect$: BehaviorSubject<string>;
+  let added$: BehaviorSubject<AddedBackground[] | undefined>;
+  let setEffect: (raw: string) => void;
  let fake: ReturnType<typeof fakePipeline>;

  function build(
@@ -102,6 +107,8 @@ describe("background effects", () => {
    return createBackgroundEffects(testScope(), {
      supported: true,
      effect$,
+      setEffect,
+      added$,
      pipeline: fake.pipeline,
      transformer: { onFirstFrame: undefined },
      ...options,
@@ -116,6 +123,8 @@ describe("background effects", () => {

  beforeEach(() => {
    effect$ = new BehaviorSubject("none");
+    added$ = new BehaviorSubject<AddedBackground[] | undefined>(undefined);
+    setEffect = vi.fn((raw: string) => effect$.next(raw));
    fake = fakePipeline();
  });

@@ -169,4 +178,63 @@ describe("background effects", () => {
      { mode: "disabled" },
    ]);
  });
+
+  it("clears a remembered effect when it cannot be honoured", () => {
+    effect$.next(`image:${shippedBackgrounds[0].id}`);
+    const effects = build({ supported: false });
+    expect(effect$.value).toBe("none");
+    expect(effects.state$.value.processor).toBeUndefined();
+  });
+
+  it("puts an added background on as its picture", async () => {
+    added$.next([{ id: "mine", url: "blob:mine" }]);
+    build();
+    await choose("added:mine");
+    expect(fake.switches).toEqual([
+      { mode: "virtual-background", imagePath: "blob:mine" },
+    ]);
+  });
+
+  it("switches between any two effects in place", async () => {
+    added$.next([{ id: "mine", url: "blob:mine" }]);
+    const shipped = shippedBackgrounds[0];
+    const options: Record<string, unknown> = {
+      none: { mode: "disabled" },
+      blur: { mode: "background-blur", blurRadius: 15 },
+      [`image:${shipped.id}`]: {
+        mode: "virtual-background",
+        imagePath: shipped.imagePath,
+      },
+      "added:mine": { mode: "virtual-background", imagePath: "blob:mine" },
+    };
+    // Each kind to each other kind, and back.
+    const order = [
+      "blur",
+      `image:${shipped.id}`,
+      "added:mine",
+      "blur",
+      "added:mine",
+      `image:${shipped.id}`,
+      "none",
+      "added:mine",
+      "none",
+      "blur",
+    ];
+    const effects = build();
+    await choose(order[0]);
+    const pipeline = effects.state$.value.processor;
+    for (const raw of order.slice(1)) await choose(raw);
+
+    expect(effects.state$.value.processor).toBe(pipeline);
+    expect(fake.switches).toEqual(order.map((raw) => options[raw]));
+  });
+
+  it("forgets an added background the device no longer keeps", () => {
+    effect$.next("added:gone");
+    build();
+    // Not before the device has said what it keeps.
+    expect(effect$.value).toBe("added:gone");
+    added$.next([]);
+    expect(effect$.value).toBe("none");
+  });
 });
@@ -27,9 +27,11 @@ import { type Behavior } from "./Behavior";
 import { type ObservableScope } from "./ObservableScope";
 import {
  type BackgroundEffect,
+  type EffectId,
  imagePathFor,
  parseEffect,
 } from "../tracks/backgroundEffectCatalog";
+import { type AddedBackground } from "../tracks/backgroundImages";

 const blurRadius = 15;

@@ -45,6 +47,10 @@ export interface BackgroundEffectsOptions {
  supported: boolean;
  /** The effect chosen, as the setting stores it. */
  effect$: Behavior<string>;
+  /** Stores a choice, to forget one that can't be honoured. */
+  setEffect: (id: EffectId) => void;
+  /** The backgrounds the device keeps, undefined until it has said. */
+  added$: Behavior<AddedBackground[] | undefined>;
  /** The background processor pipeline to be switched between effects. */
  pipeline: BackgroundProcessorWrapper;
  /** Tells, once, that a frame carrying an effect has been drawn. */
@@ -59,7 +65,14 @@ export interface BackgroundEffects {
 /** Switches the pipeline as the choice changes, for as long as the scope lasts. */
 export function createBackgroundEffects(
  scope: ObservableScope,
-  { supported, effect$, pipeline, transformer }: BackgroundEffectsOptions,
+  {
+    supported,
+    effect$,
+    setEffect,
+    added$,
+    pipeline,
+    transformer,
+  }: BackgroundEffectsOptions,
 ): BackgroundEffects {
  // Wrapped once, so the call and the preview see one processor throughout.
  const processor = fromLivekitProcessor(pipeline);
@@ -69,6 +82,19 @@ export function createBackgroundEffects(
    distinctUntilChanged(),
  );

+  combineLatest([choice$, added$])
+    .pipe(scope.bind())
+    .subscribe(([effect, added]) => {
+      if (effect.kind === "none") return;
+      if (
+        !supported ||
+        (effect.kind === "added" &&
+          added !== undefined &&
+          !added.some(({ id }) => id === effect.id))
+      )
+        setEffect("none");
+    });
+
  const drewAFrame$ = scope.behavior(
    new Observable<boolean>((subscriber) => {
      subscriber.next(false);
@@ -101,9 +127,16 @@ export function createBackgroundEffects(
  const switchOptions$ = scope.behavior<
    SwitchBackgroundProcessorOptions | undefined
  >(
-    combineLatest([state$, choice$]).pipe(
-      map(([{ processor }, effect]) =>
-        processor === undefined ? undefined : switchOptionsFor(effect),
+    combineLatest([state$, choice$, added$]).pipe(
+      map(([{ processor }, effect, added]) =>
+        processor === undefined
+          ? undefined
+          : switchOptionsFor(
+              effect,
+              effect.kind === "added"
+                ? added?.find(({ id }) => id === effect.id)?.url
+                : undefined,
+            ),
      ),
      distinctUntilChanged(deepCompare),
    ),
@@ -121,18 +154,24 @@ export function createBackgroundEffects(
  return { state$ };
 }

+/** `addedUrl` is the picture of the added background chosen, if still kept. */
 function switchOptionsFor(
  effect: BackgroundEffect,
+  addedUrl: string | undefined,
 ): SwitchBackgroundProcessorOptions {
+  const withImage = (
+    imagePath: string | undefined,
+  ): SwitchBackgroundProcessorOptions =>
+    imagePath
+      ? { mode: "virtual-background", imagePath }
+      : { mode: "disabled" };
  switch (effect.kind) {
    case "blur":
      return { mode: "background-blur", blurRadius };
-    case "shipped": {
-      const imagePath = imagePathFor(effect.id);
-      return imagePath
-        ? { mode: "virtual-background", imagePath }
-        : { mode: "disabled" };
-    }
+    case "shipped":
+      return withImage(imagePathFor(effect.id));
+    case "added":
+      return withImage(addedUrl);
    default:
      return { mode: "disabled" };
  }
@@ -19,8 +19,10 @@ import {
  type BackgroundEffectsState,
 } from "../state/BackgroundEffects";
 import { backgroundEffect } from "../settings/settings";
+import { type AddedBackground } from "./backgroundImages";
 import { flushPromises, testScope } from "../utils/test";

+const sdkSupportMock = vi.hoisted(() => vi.fn(() => true));
 const pipelines = vi.hoisted(() => ({
  built: 0,
  destroyed: 0,
@@ -41,10 +43,18 @@ vi.mock("@livekit/track-processors", () => ({
      return Promise.resolve();
    });
  }),
-  supportsBackgroundProcessors: (): boolean => true,
+  supportsBackgroundProcessors: (): boolean => sdkSupportMock(),
 }));
 const platformMock = vi.hoisted(() => ({ platform: "desktop" }));
 vi.mock("../Platform", () => platformMock);
+vi.mock("./backgroundImages", async () => {
+  const { BehaviorSubject } = await import("rxjs");
+  return {
+    addedBackgrounds: {
+      added$: new BehaviorSubject<AddedBackground[] | undefined>(undefined),
+    },
+  };
+});
 vi.mock("./BackgroundEffectTransformer", () => ({
  BackgroundEffectTransformer: vi.fn(),
 }));
@@ -77,6 +87,7 @@ describe("BackgroundEffectsProvider", () => {
    pipelines.destroyed = 0;
    pipelines.switches = [];
    platformMock.platform = "desktop";
+    sdkSupportMock.mockReturnValue(true);
    backgroundEffect.setValue("none");
  });
  afterEach(() => backgroundEffect.setValue("none"));
@@ -13,6 +13,7 @@ import { createContext, type FC, type JSX, use } from "react";

 import { backgroundEffect as backgroundEffectSetting } from "../settings/settings";
 import { BackgroundEffectTransformer } from "./BackgroundEffectTransformer";
+import { addedBackgrounds } from "./backgroundImages";
 import { type Behavior } from "../state/Behavior";
 import { type ObservableScope } from "../state/ObservableScope";
 import {
@@ -53,6 +54,8 @@ export function createAppBackgroundEffects(
  return createBackgroundEffects(scope, {
    supported: supportsBackgroundProcessors(),
    effect$: backgroundEffectSetting.value$,
+    setEffect: backgroundEffectSetting.setValue,
+    added$: addedBackgrounds.added$,
    pipeline: new BackgroundProcessorWrapper(transformer, "background-effect"),
    transformer,
  });
@@ -15,6 +15,7 @@ import {
  serializeEffect,
  shippedBackgrounds,
 } from "./backgroundEffectCatalog";
+import { maxAddedBackgrounds } from "./backgroundImages";

 describe("the chosen background effect", () => {
  test("round-trips through its stored form", () => {
@@ -22,6 +23,7 @@ describe("the chosen background effect", () => {
      { kind: "none" },
      { kind: "blur" },
      ...shippedBackgrounds.map(({ id }) => ({ kind: "shipped" as const, id })),
+      { kind: "added", id: "d3b07384" },
    ];
    for (const effect of effects)
      expect(parseEffect(serializeEffect(effect))).toEqual(effect);
@@ -30,6 +32,7 @@ describe("the chosen background effect", () => {
  test("falls back to no effect when the stored form names nothing we ship", () => {
    expect(parseEffect("image:gone")).toEqual({ kind: "none" });
    expect(parseEffect("")).toEqual({ kind: "none" });
+    expect(parseEffect("added:")).toEqual({ kind: "none" });
  });

  test("reads a stored value that is not a string as no effect", () => {
@@ -37,6 +40,14 @@ describe("the chosen background effect", () => {
      expect(parseEffect(raw)).toEqual({ kind: "none" });
  });

+  test("fills the grid at the limit and one short of it", () => {
+    // No effect, blur and the shipped ones, then the added ones.
+    const fixed = 2 + shippedBackgrounds.length;
+    expect((fixed + maxAddedBackgrounds) % 3).toBe(0);
+    // One short, the add tile takes the last place.
+    expect((fixed + maxAddedBackgrounds - 1 + 1) % 3).toBe(0);
+  });
+
  test("gives every shipped background an image to draw", () => {
    for (const { id } of shippedBackgrounds)
      expect(imagePathFor(id)).toBeTruthy();
@@ -22,16 +22,18 @@ export const shippedBackgrounds: ShippedBackground[] = [
 export type BackgroundEffect =
  | { kind: "none" }
  | { kind: "blur" }
-  | { kind: "shipped"; id: string };
+  | { kind: "shipped"; id: string }
+  | { kind: "added"; id: string };

 /** An effect as the setting stores it, and as the menu names its option. */
-export type EffectId = "none" | "blur" | `image:${string}`;
+export type EffectId = "none" | "blur" | `image:${string}` | `added:${string}`;

 export const noEffect: BackgroundEffect = { kind: "none" };

 /**
- * Reads a stored effect; one we no longer ship reads as no effect. Stored by
- * hand or by another build, the value need not even be a string.
+ * Reads a stored effect; one we no longer ship reads as no effect. Whether an
+ * added one is still kept only the device knows. Stored by hand or by another
+ * build, the value need not even be a string.
 */
 export function parseEffect(raw: unknown): BackgroundEffect {
  if (typeof raw !== "string") return noEffect;
@@ -41,6 +43,10 @@ export function parseEffect(raw: unknown): BackgroundEffect {
    if (shippedBackgrounds.some((b) => b.id === id))
      return { kind: "shipped", id };
  }
+  if (raw.startsWith("added:")) {
+    const id = raw.slice("added:".length);
+    if (id) return { kind: "added", id };
+  }
  return noEffect;
 }

@@ -50,6 +56,8 @@ export function serializeEffect(effect: BackgroundEffect): EffectId {
      return "blur";
    case "shipped":
      return `image:${effect.id}`;
+    case "added":
+      return `added:${effect.id}`;
    default:
      return "none";
  }
@@ -0,0 +1,172 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { IDBFactory } from "fake-indexeddb";
+
+import {
+  AddedBackgrounds,
+  type BackgroundImageStorage,
+  IndexedDBImageStorage,
+  type KeptImage,
+  maxAddedBackgrounds,
+  prepareImage,
+  UnusableImage,
+} from "./backgroundImages";
+import { flushPromises } from "../utils/test";
+
+describe("AddedBackgrounds", () => {
+  beforeEach(() => {
+    let n = 0;
+    vi.spyOn(URL, "createObjectURL").mockImplementation(() => `blob:${++n}`);
+  });
+
+  it("offers what the device keeps, oldest first", async () => {
+    const image = new Blob(["x"], { type: "image/png" });
+    const store = new AddedBackgrounds(
+      memoryStorage([
+        { id: "later", image, addedAt: 2 },
+        { id: "earlier", image, addedAt: 1 },
+      ]),
+      asGiven,
+    );
+    expect(store.added$.value).toBeUndefined();
+    await flushPromises();
+    expect(store.added$.value?.map(({ id }) => id)).toEqual([
+      "earlier",
+      "later",
+    ]);
+  });
+
+  it("keeps an added image and offers it after the others", async () => {
+    const storage = memoryStorage();
+    const store = new AddedBackgrounds(storage, asGiven);
+    await flushPromises();
+    const id = await store.add(new Blob(["x"], { type: "image/png" }));
+    expect(store.added$.value?.map((a) => a.id)).toEqual([id]);
+    expect((await storage.list()).map((k) => k.id)).toEqual([id]);
+  });
+
+  it("keeps the prepared image, not the file", async () => {
+    const storage = memoryStorage();
+    const prepared = new Blob(["y"], { type: "image/webp" });
+    const store = new AddedBackgrounds(storage, async () =>
+      Promise.resolve(prepared),
+    );
+    await store.add(new Blob(["x"], { type: "image/png" }));
+    expect((await storage.list())[0].image).toBe(prepared);
+  });
+
+  it("keeps nothing of a file it refuses", async () => {
+    const storage = memoryStorage();
+    const store = new AddedBackgrounds(storage, async () =>
+      Promise.reject(new UnusableImage("animated")),
+    );
+    await flushPromises();
+    await expect(store.add(new Blob(["x"]))).rejects.toThrow(UnusableImage);
+    expect(await storage.list()).toEqual([]);
+    expect(store.added$.value).toEqual([]);
+  });
+
+  it("keeps no more than the grid holds", async () => {
+    const storage = memoryStorage();
+    const store = new AddedBackgrounds(storage, asGiven);
+    for (let i = 0; i < maxAddedBackgrounds; i++)
+      await store.add(new Blob([`${i}`]));
+    await expect(store.add(new Blob(["more"]))).rejects.toThrow(RangeError);
+    expect(await storage.list()).toHaveLength(maxAddedBackgrounds);
+  });
+
+  it("forgets a removed image, and lets its picture go", async () => {
+    const revoke = vi
+      .spyOn(URL, "revokeObjectURL")
+      .mockImplementation(() => {});
+    const storage = memoryStorage();
+    const store = new AddedBackgrounds(storage, asGiven);
+    await flushPromises();
+    const first = await store.add(new Blob(["a"]));
+    const second = await store.add(new Blob(["b"]));
+    const url = store.added$.value![0].url;
+
+    await store.remove(first);
+    expect(store.added$.value?.map((a) => a.id)).toEqual([second]);
+    expect((await storage.list()).map((k) => k.id)).toEqual([second]);
+    expect(revoke).toHaveBeenCalledWith(url);
+  });
+
+  it("offers nothing where the browser keeps nothing", async () => {
+    const store = new AddedBackgrounds(null);
+    await flushPromises();
+    expect(store.added$.value).toEqual([]);
+    await expect(store.add(new Blob(["x"]))).rejects.toThrow();
+  });
+
+  it("offers none, rather than waiting, where the device can't be read", async () => {
+    const unreadable: BackgroundImageStorage = {
+      ...memoryStorage(),
+      list: async () => Promise.reject(new Error("storage cleared")),
+    };
+    const store = new AddedBackgrounds(unreadable);
+    await flushPromises();
+    expect(store.added$.value).toEqual([]);
+  });
+});
+
+describe("prepareImage", () => {
+  // Refused before anything is decoded, which only a real browser could do.
+  it("refuses a file that isn't an image", async () => {
+    await expect(
+      prepareImage(new Blob(["x"], { type: "text/plain" })),
+    ).rejects.toEqual(new UnusableImage("not-an-image"));
+  });
+
+  it("refuses an animated type where the browser can't count frames", async () => {
+    expect(globalThis.ImageDecoder).toBeUndefined();
+    await expect(
+      prepareImage(new Blob(["GIF89a"], { type: "image/gif" })),
+    ).rejects.toEqual(new UnusableImage("animated"));
+  });
+});
+
+describe("IndexedDBImageStorage", () => {
+  it("keeps images across sessions until they are deleted", async () => {
+    const indexedDB = new IDBFactory();
+    const image = new Blob(["x"], { type: "image/webp" });
+    const first = new IndexedDBImageStorage(indexedDB);
+    await first.put({ id: "a", image, addedAt: 1 });
+    await first.put({ id: "b", image, addedAt: 2 });
+
+    // A session of its own, as after a reload.
+    const second = new IndexedDBImageStorage(indexedDB);
+    expect(
+      (await second.list()).map(({ id, addedAt }) => [id, addedAt]),
+    ).toEqual([
+      ["a", 1],
+      ["b", 2],
+    ]);
+    await second.delete("a");
+    expect((await first.list()).map(({ id }) => id)).toEqual(["b"]);
+  });
+});
+
+// Decoding needs a real browser; the end-to-end checks cover it.
+const asGiven = async (file: Blob): Promise<Blob> => Promise.resolve(file);
+
+function memoryStorage(kept: KeptImage[] = []): BackgroundImageStorage {
+  return {
+    list: async (): Promise<KeptImage[]> => Promise.resolve([...kept]),
+    put: async (image): Promise<void> => {
+      kept.push(image);
+      return Promise.resolve();
+    },
+    delete: async (id): Promise<void> => {
+      const index = kept.findIndex((k) => k.id === id);
+      if (index !== -1) kept.splice(index, 1);
+      return Promise.resolve();
+    },
+  };
+}
@@ -0,0 +1,220 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { BehaviorSubject } from "rxjs";
+import { logger } from "matrix-js-sdk/lib/logger";
+
+import { type Behavior } from "../state/Behavior";
+
+export const maxAddedBackgrounds = 5;
+
+/** The longest edge kept; the pipeline scales every image to the camera. */
+export const maxStoredEdge = 1920;
+
+/** Why a file can't be used as a background. */
+export type UnusableReason = "not-an-image" | "animated" | "undecodable";
+
+export class UnusableImage extends Error {
+  public constructor(public readonly reason: UnusableReason) {
+    super(reason);
+    this.name = "UnusableImage";
+  }
+}
+
+/** A background the user added, as the menu and the pipeline use it. */
+export interface AddedBackground {
+  id: string;
+  url: string;
+}
+
+/** A background the user added, as it is kept on the device. */
+export interface KeptImage {
+  id: string;
+  image: Blob;
+  addedAt: number;
+}
+
+/** Where added backgrounds are kept. */
+export interface BackgroundImageStorage {
+  list(): Promise<KeptImage[]>;
+  put(image: KeptImage): Promise<void>;
+  delete(id: string): Promise<void>;
+}
+
+/** The backgrounds this device keeps, which never leave it. */
+export class AddedBackgrounds {
+  private readonly subject$ = new BehaviorSubject<
+    AddedBackground[] | undefined
+  >(undefined);
+  /** Undefined until what the device keeps has been read. */
+  public readonly added$: Behavior<AddedBackground[] | undefined> =
+    this.subject$;
+
+  public constructor(
+    private readonly storage: BackgroundImageStorage | null,
+    private readonly prepare: (file: Blob) => Promise<Blob> = prepareImage,
+  ) {
+    this.read().catch((e) => {
+      logger.warn("Could not read added backgrounds", e);
+      this.subject$.next([]);
+    });
+  }
+
+  private async read(): Promise<void> {
+    const kept = (await this.storage?.list()) ?? [];
+    kept.sort((a, b) => a.addedAt - b.addedAt);
+    this.subject$.next(
+      kept.map(({ id, image }) => ({ id, url: URL.createObjectURL(image) })),
+    );
+  }
+
+  /**
+   * Keeps a file as a background, and answers with its id. Throws
+   * {@link UnusableImage} for a file that can't be used, and a RangeError
+   * once maxAddedBackgrounds are kept.
+   */
+  public async add(file: Blob): Promise<string> {
+    if (this.storage === null)
+      throw new Error("This browser keeps no backgrounds");
+    const image = await this.prepare(file);
+    if ((await this.storage.list()).length >= maxAddedBackgrounds)
+      throw new RangeError(
+        `${maxAddedBackgrounds} backgrounds are kept already`,
+      );
+    const kept: KeptImage = {
+      id: crypto.randomUUID(),
+      image,
+      addedAt: Date.now(),
+    };
+    await this.storage.put(kept);
+    this.subject$.next([
+      ...(this.subject$.value ?? []),
+      { id: kept.id, url: URL.createObjectURL(image) },
+    ]);
+    return kept.id;
+  }
+
+  public async remove(id: string): Promise<void> {
+    await this.storage?.delete(id);
+    const current = this.subject$.value ?? [];
+    const gone = current.find((a) => a.id === id);
+    if (gone) URL.revokeObjectURL(gone.url);
+    this.subject$.next(current.filter((a) => a.id !== id));
+  }
+}
+
+/**
+ * Refuses what can't be used, reduces what is larger than is kept, and lays
+ * every image on an opaque ground: a background has to cover what is behind
+ * it, so a transparent pixel would be a hole in it.
+ */
+export async function prepareImage(file: Blob): Promise<Blob> {
+  if (!file.type.startsWith("image/")) throw new UnusableImage("not-an-image");
+  if (await isAnimated(file)) throw new UnusableImage("animated");
+
+  let bitmap: ImageBitmap;
+  try {
+    bitmap = await createImageBitmap(file);
+  } catch (e) {
+    logger.debug("Could not decode the chosen file", e);
+    throw new UnusableImage("undecodable");
+  }
+  try {
+    const scale = Math.min(
+      1,
+      maxStoredEdge / Math.max(bitmap.width, bitmap.height),
+    );
+    const canvas = new OffscreenCanvas(
+      Math.round(bitmap.width * scale),
+      Math.round(bitmap.height * scale),
+    );
+    const context = canvas.getContext("2d");
+    if (!context) throw new UnusableImage("undecodable");
+    context.fillStyle = "black";
+    context.fillRect(0, 0, canvas.width, canvas.height);
+    context.drawImage(bitmap, 0, 0, canvas.width, canvas.height);
+    return await canvas.convertToBlob({ type: "image/webp", quality: 0.9 });
+  } finally {
+    bitmap.close();
+  }
+}
+
+// Read from the file, not its type: a still and an animated WebP share one.
+async function isAnimated(file: Blob): Promise<boolean> {
+  if (typeof ImageDecoder === "undefined") return /gif|apng/.test(file.type);
+  try {
+    const decoder = new ImageDecoder({
+      data: await file.arrayBuffer(),
+      type: file.type,
+    });
+    // Some browsers have no selected track until the tracks are ready.
+    await decoder.tracks.ready;
+    await decoder.completed;
+    return (decoder.tracks.selectedTrack?.frameCount ?? 1) > 1;
+  } catch (e) {
+    logger.debug("Could not read the frame count, judging by type", e);
+    return /gif|apng/.test(file.type);
+  }
+}
+
+const DB_NAME = "element-call-background-images";
+const STORE = "backgrounds";
+
+export class IndexedDBImageStorage implements BackgroundImageStorage {
+  private db?: Promise<IDBDatabase>;
+
+  public constructor(private readonly indexedDB: IDBFactory) {}
+
+  private async open(): Promise<IDBDatabase> {
+    return (this.db ??= new Promise((resolve, reject) => {
+      const request = this.indexedDB.open(DB_NAME, 1);
+      request.onupgradeneeded = (): void => {
+        request.result.createObjectStore(STORE, { keyPath: "id" });
+      };
+      request.onsuccess = (): void => resolve(request.result);
+      request.onerror = (): void => reject(request.error);
+    }));
+  }
+
+  private async run<T>(
+    mode: IDBTransactionMode,
+    body: (store: IDBObjectStore) => IDBRequest<T>,
+  ): Promise<T> {
+    const db = await this.open();
+    return new Promise((resolve, reject) => {
+      const request = body(db.transaction(STORE, mode).objectStore(STORE));
+      request.onsuccess = (): void => resolve(request.result);
+      request.onerror = (): void => reject(request.error);
+    });
+  }
+
+  public async list(): Promise<KeptImage[]> {
+    return this.run<KeptImage[]>("readonly", (s) => s.getAll());
+  }
+
+  public async put(image: KeptImage): Promise<void> {
+    await this.run("readwrite", (s) => s.put(image));
+  }
+
+  public async delete(id: string): Promise<void> {
+    await this.run("readwrite", (s) => s.delete(id));
+  }
+}
+
+function openStorage(): BackgroundImageStorage | null {
+  // Merely reading indexedDB throws where it is disabled.
+  try {
+    return globalThis.indexedDB
+      ? new IndexedDBImageStorage(globalThis.indexedDB)
+      : null;
+  } catch (e) {
+    logger.warn("Could not reach IndexedDB", e);
+    return null;
+  }
+}
+
+export const addedBackgrounds = new AddedBackgrounds(openStorage());
Author	SHA1	Message	Date
fkwpandClaude Opus 5.5	fb4cbc72e2	Remove a background of one's own - A cross on the tile's top-right corner removes an added background, critical-coloured at rest and named by its tooltip, as design draws it. The one in force offers none, since taking it away would leave nothing chosen; the view model refuses it too. - The cross sits beside the item rather than in it, which would take the press first and choose the tile, and isn't a control of its own, so the menu keeps one keyboard model: Delete or Backspace on the tile does the same, and the tile says so with aria-keyshortcuts. - Removed from IndexedDB and its picture released. End to end on Chromium and Firefox, a background removed by Delete is still gone after a reload. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-06 10:33:22 +01:00
fkwp	bac9811829	Merge pull request #4288 from element-hq/spec/background-effects/8-own-backgrounds Add a background of one's own, kept on this device	2026-11-06 10:33:17 +01:00
renovate[bot]andJohannes Marbach	a2cfc2af93	Update ghcr.io/element-hq/element-web:develop Docker digest to 49104e3 (#4415 ) * Update ghcr.io/element-hq/element-web:develop Docker digest to e063472 * Fix tests * Dismiss further toasts * Close even more toasts * Yet more toast fixes * Toast fixes all over --------- Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com> Co-authored-by: Johannes Marbach <n0-0ne+github@mailbox.org>	2026-11-06 07:24:53 +00:00
Valere Fedronic	dcb2b9e8f6	Merge pull request #4418 from element-hq/valere/bug_fix_no_config_uncaught_error Fix: Uncaught exception in downloadConfig	2026-11-05 16:30:40 +01:00
fkwpandClaude Opus 5.5	373b1e0fc0	Guard what can be added as a background - Five of one's own at most, so the grid is whole: at the limit the add tile goes, and it comes back once one is removed. The store holds the limit too. - An added image is refused if it isn't an image, is animated, or can't be decoded; reduced to 1920px on its longest edge; and laid on an opaque ground, since a transparent pixel would be a hole in the background. - Animation is read from the file, as a still and an animated WebP share a type. Chromium has no selected track until the decoder's tracks are ready; without waiting for them an animated GIF got through. - A refusal says why, in place of the notice, and is scrolled into view. It can be dismissed, is gone once the menu closes, and the next shows even if it reads the same. What was in force stays. - End to end on Chromium and Firefox, from what the device then keeps: an animated GIF is refused with its message, a 4000x3000 image is kept at 1920x1440, and a half transparent one is kept opaque. All three fail with the preparation bypassed. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-05 16:20:33 +01:00
fkwpandClaude Opus 5.5	1bc372b587	Add a background of one's own, kept on this device - An add tile after the pictures opens the file picker, and the image chosen joins the backgrounds on offer without being put on; it is in force once chosen, like a shipped one. The tile is a command rather than a choice, so a menu item beside the radios, and it isn't offered where effects can't run. - Kept in IndexedDB on this device and never sent anywhere, behind a small interface, so the unit tests use an in-memory store; the IndexedDB store itself is tested against fake-indexeddb, a new dev dependency. - The picker takes the focus, which the menu reads as a click elsewhere, so the menu holds itself open until a file is chosen or the picker is cancelled. - A chosen image the device no longer keeps, as after its storage is cleared, falls back to no effect once the device has said what it keeps. - Switching is checked between any two kinds of effect. End to end on Chromium and Firefox: an added image shows in the preview once chosen; once it is in force, no request carries the file or the copy kept, which a deliberate upload fails; chosen, it is in force again after a reload, gone once storage is cleared, and can be added again. - Kept as given here; what can be added is checked in the commit after. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-05 16:20:33 +01:00
fkwp	82ba51ea6a	Merge pull request #4287 from element-hq/spec/background-effects/7-hold-choice Hold the chosen effect across calls, and forget one that can't run	2026-11-05 16:20:27 +01:00
fkwp	07aaa326d2	Merge pull request #4286 from element-hq/spec/background-effects/6-no-frame-of-the-room Check that background effects never publish the room and stay inside the call	2026-11-05 16:20:16 +01:00
fkwpandClaude Opus 5.5	741dab6dbb	Hold the chosen effect across calls, and forget one that can't run - A remembered effect this browser can't run is cleared rather than kept, as the menu already showed no effect in force there. - A camera turned off and on again with an effect chosen gets the same pipeline as its track arrives, neither rebuilt nor switched again. - End to end, on Chromium and Firefox: the effect chosen before a call is still chosen, and worn, in the next call after leaving; and a second tab still shuts the first down with the existing "Opened in another tab" error while an effect runs. - Switching camera and sharing a screen are checked by hand: they need two cameras and a screen, which the fake devices don't give yet. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-05 15:30:25 +01:00
Timo K.andClaude Fable 5.1	4f184f504d	Expect the join to fetch no model, as it adopts the lobby's pipeline The e2e check held back the model download at the join and required one, since the pipeline used to be built again for the call's track. The join now takes the lobby's running pipeline over, so no download happens, and the check says so. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>	2026-11-05 15:30:25 +01:00
fkwpandClaude Opus 5.5	ecf2cbc71e	Check the background effects stay inside the call everywhere - The standalone app at five window sizes, from a large desktop to a phone-shaped 360x640, on Chromium and Firefox: the camera menu stays inside the window, which is the call area there, and the last effect can still be scrolled to and chosen. - As a component in a host page, and as a widget in Element Web: a picture chosen reaches the preview, so the pipeline's model and WebAssembly load from those builds, and in a small container the last effect is reached and chosen. - Compound portals the menu to the page and takes no container for it, so there it has none of the component's scoped styles, as the microphone menu has none. - The colour checks the three share live in playwright/utils. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-05 14:50:09 +01:00
fkwpandClaude Opus 5.5	fb38a1e6e0	Check that no camera start publishes a frame of the room - A host in the call records every frame of every video track it receives from the moment the track arrives. A guest with a picture chosen joins, or turns the camera on in the call from off at joining or from off in the call; none of the guest's frames may be closer to the camera image than to the picture. A guest with no effect fails it. - The preview's track stopping destroys the shared pipeline, so the call's track builds it again. That build is held back as long as the slower route takes, and publishing still waits for it; each check that holds the model back also checks that it did. - The first build survives the preview camera turned off and on while it runs, which is what running builds one at a time is for. - The camera's colour is taken once the preview shows it; taken earlier it was black, which let frames of the room pass as the picture. The camera checks wait for the call itself, as the lobby has a camera button of its own. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>	2026-11-05 14:50:09 +01:00