Can You have GIFs as Sigs / Prof Pics / Avatars?

[Mrs. Peter Quinn]

I was wondering whether this was possible? I think I've seen a few people with gifs (@Thingimubob?) If so, how?

If it's now allowed for some reason I might suggest in future if TRF re-instates some sort of premium membership thing, paying members be allowed to do this. I also wonder whether members could have bigger profile pictures?