Zryder, you just click the add avatar button in you account. You really just need to spend a couple of minutes exploring the options, they are the usual php type options available of other forums (with a few extras).
The options for inserting image, insert url etc are all in the box where you type your messages, all in plain sight.
It tells you in the FAQ post the sizes allowed for avatars, images etc and the wingnut kindlyoffers to resize the avatar for people that can't do it themselves. Like I said, it's all there to see, you just need to spend a few minutes raeding it.