Well to get a normal type like JAG has you have to be a very notable member for some reason or another, and the mods have to decide to give it to you.

To get an Url avatar you have to go through the mods, I got one (I was a guinea pig for the system) and so did one other person I think. To see Url avatars you have to go to your preferences in the user cp and select see url avatars. You should then shut off normal ones as you will see a person's normal avatar in the second place if they don't have an Url avatar.