How to give usergroup icons and stuff?

[pportuese]

I made a usergroup for people who have donated to the site, but how do I give them specific pictures under their names. Ones where nobody else can add them in themselves.
And how do I make it so that when they pay it does it on it's own?

[pportuese]

Nobody? I want to add it under their username. How do I do this?