Originally posted by Gashog I wouldn't.
My philosophy has been you should get whatever you can out of your work before it is stolen or falls out of favor.
It's irritating when it happens but what has it really cost you? If the answer is "lots of money!" then sue.
I don't publish my images. I have a thousand online right now but they are private. My Flickr has some nice pictures that I have already used up, are not important, or have already been stolen.
I think you're a bit late. Post was made 8 months ago.