it's not a silly question at all lol it's the most commonly asked one! those pics at the end of our posts are called sigs or signatures as they "sign" our posts, here is my tutorial on how to put one in, this is a thread here on the Roo so it's safe to click my link ...
How to use the Jokeroo Uploader to post pics,inc Signature Pics
it's easy to do, just a bit difficult to explain lol