So far I only got it in one thread. http://sportstwo.com/threads/210691-Imagine-you-are-George-Zimmerman/page13 I haven't tested every thread obviously but I think it is just a photo linked from some wrestling website that is the issue on that thread.
It's a picture in someone's post. I deleted the picture. It should stop the messages from happening to you for now. (The URL of the image was a site that may contain malware) I don't think the image itself is harmful.