Find a pic with its own web address, then simply type it inside the avatar field in your profile. Sometimes, you will hit one that does not work, so just try again!Google for them! For instance, a thumbnail of Tolkki would be:

But, leave off the image tags for an avatar---image tags are just for signatures and posting pics.
Personally, I find thumbnails best to use because they are basicly sized, and don't look weird--a large pic has to be sized down,and the end result can be disappointing.
Hope what I said helps.

"Your life is yours, and yours alone. Rise up and live it!"
Bob: I don't believe in God.
Archangel Michael: That's OK, Bob, because He doesn't believe in you, either!~Legion~