Our support for animated GIFs (and PNGs) is rather pathetic.
We basically bail out as soon as it becomes too much to resize, which protects the website, but doesn't really give a good user experience. See also: https://commons.wikimedia.org/wiki/Category:Animated_GIF_files_affected_by_MediaWiki_restrictions
T63711 and T25063
- Default everything to single frame thumbs
- Add a library to JS load animated images on demand
- Add an option: autoplay to give current playback behavior.
- Simply encode all animated GIFs as WebM and use those: T105276: Convert animated images (animGIF, APNG) to HTML5 video