animated

One animated PNG, known as APNG: a 5 second looping clip of 34 KB. APNG looks like an ordinary PNG, and the file name ends in .png, but it holds many frames. Software that does not know APNG shows only the first frame, so it is a quiet way to find tools that ignore animation without any error. Use it to test whether your site keeps the animation, whether a thumbnail is a still or a moving image, and whether a conversion to GIF or WebP keeps every frame. Compare the size with the GIF and WebP versions.