why not? i dont unnderstand your position, dont you have a copyright notice on you site to protect you from someone brazenly nicking all your efforts? if you saw someone using your images all over their site with out permission or reference to source, wouldnt you ask them to stop/ask...
i dont believe this is the case, they haven't sought to protect the image so it loses the trademark protection. if they even applied for it back then, which is unlikly. you'll recall that Arsenal changed their logo a few years ago specifically to be able to protect the new one and stop the tat...