- Use PNG format instead of JPEG for transparency support - Non-strict mode only resizes if image width > target width - Replace CATALOGUE_BACKGROUND_IMAGES_COLOR with CATALOGUE_BACKGROUND_IMAGES_RGBA (tuple default (0,0,0,0)) - Move all inline imports to top of test file - Add test_resize_non_strict_no_upscale test case - Add comment explaining settings.DEBUG guard for media serving