Animate Avatar in forum?

Morning

I have seen others with avatars that are animated, but for some reason the ones i try to add wont animate. If i load the gif file in firefox, it works great. I upload it here in User CP, but it doesnt go through the animation.

Never really used avatars b4 so i was just messing around with this bored at work, but is there some trick? lol ya sounds dumb, but its working for others and not me,

Cheers!