It is possible to make "Animations" whithin a WebP File. The Idea behind this File-Fomat is a replacement for the "classic" Formats like PNG, JPG and GIF. The GranTourismo saves all "Screenshots" from the Playstation as WebP and modern CMS-Systems like Wordpress are able to handle this files. Modern (Major) Browsers can display WebP since 2019 (Firefox) and 2020 (Edge, Chrome, Safari) . WebM is supported by these Browsers too and the PS5 save all "Videos" in this Format.

The main specs for WebP are:

Conclusion: It would be great to have an WebP/WebM support in Secondlife

For Example: https://mathiasbynens.be/demo/animated-webp <- an animated WebP

Deeper Informations from Wikipedia: https://en.wikipedia.org/wiki/WebP

Alternative Videoformat WebM: https://en.wikipedia.org/wiki/WebM

I think due to file size a lot of websites these days use Webp format to store most image files? I've never used it myself yet, because I'm not aware of any sites that allow directly uploading it, but a new image format in SL that can include animation would be very nice, and Webp might be the solution, similar to how we're getting GLTF for models. Webp is also a smaller filesize than Gif, generally all-around better, it's just newer.

I imagine if it detects animation, we could upload it as an animated texture so even in the inventory preview it pre-animates, though I'm unsure if scripts could control speed anymore. (but those could just do the old way I suppose?)

I'd be willing to pay extra upload cost for uploading animated textures though, similar to how 2k costs more. Animated particles would be very cool to see!

Not sure adding a file format to SL that was more or less purged off the web and replaced by video formats because it was so inefficient in terms of file size would be a good idea.

Maybe uploading short videos with a limited number of frames for that purpose would be more useful.