1. The image your seeing was posted in these forums.
2. The image is in place of the "Online" indicator of vBulletin. (
3. The URL to the image, as you reported, is the same as the "Online" indicator. ( stuntbikes.net/forums/images/statusicon/user_online.gif )
So, for some odd reason instead of seeing the "little green circle" when someone is online, you were seeing a picture that was posted a little while ago. I'm curious if simply clicking your browser refresh would have resolved this cached issue, as I suspect.