A Community for people to create posts with GIFs, MP4s or WEBPs - anything that's animated and reasonably short.
Images can be often be hosted directly on Lemmy, or on external sites such as https://imgur.com or https://catbox.moe.
Thumbnails are pretty much always going to be a "no" for mp4 since lemmy backend doesn't generate a thumbnail image or provide the thumbnail_url attribute in the post for them. A lot of it has to do with how pict-rs is configured and what format it gets converted into. I believe .webm will generate a thumbnail or at least, but the admins would have to configure pict-rs to use webm.
Loop is going to be client-specific since you have to add that to the video element.
Thank you for the info. I've been wading through pict-rs trying to figure out what it does, but the only thing I really learnt was that it's very configurable. I'm trying .webp next, but yeah, the last time I saw a .webm uploaded, it wasn't playing at all.