I've see a couple people with animated gif avatars.

Anyone have a way to get this:

or this: http://i.imgur.com/k29CC.gif (just close-up on Cruz salsa, no surrounding or watermark)

...into a files size that's compatible for an avatar?
Note: The maximum size of your custom image is 75 by 75 pixels or 19.5 KB (whichever is smaller).