How to add animations to a avatar?

[Cptcreeper64!]

I've see Chris's profile and a few other peoples' profile, but how do you make your avatar an animation. And if you can, can you find a cool creeper animation and show me how to add it

 

[imtotallychris]

It's like adding a regular avatar., but a .gif file, It has to be the same length though, 200x200

 

[Cptcreeper64!]

Thx

 

[imtotallychris]

Welcome