>>17136Now that I think about it, it could be potentially beneficial to make all thumbnails use the webp format, regardless of what format the file itself is.
The only possible issue I can think of here is that if it doesn't convert all thumbnails to webp and someone is using an old browser without webp support, they would still be able to see the thumbnail, if not the file itself. But if it does do this and someone is using an old browser, they wouldn't even be able to see the thumbnail, and the site would look broken.
While I was reading about webp support, I noticed a site saying that if a browser doesn't support it, you can just use a jpg or a png file in addition to a webm file, but that kind of defeats the purpose here.