First click on the link under the image.. Then copy the URL from the address bar at the top of your screen. Close that window and Click on the FORUM link on the top of the XGC page. then, On the left side of your screen click on the link that reads USER CP. next, Scroll down and on the left side click on the link that says EDIT SIGNATURE. In the text box click the little yellow icon that has what looks like a mountain in it which is the 'insert picture' button. Paste the URL in the window that pops up and hit ok.. That should do it..
If you have a problem go to the 101st chat room. If you've never been there before, click on the chat button on the top of the xgc page and log in, Scroll down to find the XGC 101ST XK chatroom. I will be in there to help you.