Some videos allowed?

[bsteer]

This is why GIF is generally considered an outdated format and not used any more on the web. Modern video formats are just way more efficient. Probably you would get the same quality with only a few percent of the file size. So I think it would make a lot more sense to instead support video files, but keep the small file size limit. How a creature moves (e.g. bird flight) can be quite a distinguishing feature, especially from a distance when other visual clues are less apparent.