How do people make head gifs in the texture section and have them rotating?

I use GIMP for this.
Filters -> Animation -> Spinning Globe
I usually put it on 63 frames, but you can play around and chose the frames right for you. (this changes the speed)
And you save it by using the "Export" function and choose .gif.
Don't forget to click on the "save as infinite loop" (or something that sounds like that)

Personally, ive never seen it, but if someone did that'd be pretty cool. maybe try the artwork section of the forums?? it could be in there. I dont honestly think anyone in here will have seen it since they are beginners, and probably havent played much outside of low-rank lobbies.