diff --git a/lib/cartodb/api/middlewares/check-static-image-format.js b/lib/cartodb/api/middlewares/check-static-image-format.js
new file mode 100644
index 00000000..d72fcb81
--- /dev/null
+++ b/lib/cartodb/api/middlewares/check-static-image-format.js
@@ -0,0 +1,11 @@
+const VALID_IMAGE_FORMATS = ['png', 'jpg', 'jpeg'];
+
+module.exports = function checkStaticImageFormat () {
+    return function checkStaticImageFormatMiddleware (req, res, next) {
+        if(!VALID_IMAGE_FORMATS.includes(req.params.format.toLowerCase())) {
+            return next(new Error(`Unsupported image format "${req.params.format}"`));
+        }
+
+        next();
+    };
+};