This account is only meant to be a tutorial for animated avatars.

Go get a gif and then resize it to something close to 100x100 and square, you have to make sure the gif is under like 500kb or something to be safe, I like 200kb myself thats what the shuckle gif is. Open up in a hex editor, I like HxD and then scroll to the bottom until you find something like:

http://puu.sh/gxf8H/5fb1fd5817.png

the ..; delete that from the end and then paste this thing in its place at the end: http://pastebin.com/6d4VEgLG (no not the LINK but numbers/letters inside the link) and then upload, it will give u an error when you upload it. just refresh or delete cache to see if it worked.

also you might be able to put other things in a picture and upload it using the same thing, dont put bad code in there tho ;) the site might try to execute it and no seizure giving gifs either

also upload a still image avatar first, and that will be your display avatar in games, the animation will only work on your profile.