Here is the trick - you gotta get yourself a gravatar by going to http://gravatar.com or http://en.gravatar.com/. Then your picture will show up automatically in places where you post something which is associated with your email address. In other words, your profile in the forum is associated with a particular email address. If you use this email address when you upload your picture to the gravatar website, then it will automatically show up in the forum. That's how mine is showing up.