edit: well almost perfect, it blocks Cyber's SimHq logo in his sig too.
Ok you blocked the "server" (don't know if that's the correct term but follow me here!)
First, can you figure out how to undo that? Not sure if I can help do that, but if you can then do this:
Right click on the cheerleaders and click "adblock" and "block this ad"
When the pop up comes up click "looks good" and in the next pop up uncheck the top two and then check the bottom one (I'm using Cyberkuts image in my example, just ignore that file name)
That way you are blocking ONLY that one image. :