supportsOption("dds_dxt1_rgb","set the pixel format of DXT1 encoded images to be RGB");
supportsOption("dds_dxt1_rgba","set the pixel format of DXT1 encoded images to be RGBA");
supportsOption("dds_dxt1_detect_rgba","For DXT1 encode images set the pixel format according to presence of transparent pixels.");
And set the default not to modify and detect the RGB or RGBA pixel format for DXT images.