Do you own the photo, or does it belong to xMarine? Are you hosting it with his permission? Make sure you even know who is the copyright holder first.
Second, we can agree that the image was in violation of copyright but falls within the fair use doctrine because it is parody. Are you willing to go to court and spend all that money to find out if they agree?
Regardless, and contrary to how Lute seems to be reading it, this was far from a respectful request to remove anything. Threatening a lawsuit based on your own shaky knowledge of copyright law does not seem like a wise first step. Perhaps a PM to the parties in question would have been a far more suitable course of action all things considered. Crying to the General Discussion crowd doesn't endear you to anyone.
In any event, the joke has run its course, and I naturally expect that the images/avatars will disappear as a consequence.
-- Todd/Leviathn