Hey settle down now, you've read my post and taken it the wrong way. That applies to the U.S. and the U.S. only. Contrary to what some Americans appear to beleive, it's not the only country in the world, now I don't know that much about U.S. law because I don't live there but I've been told/taught it's only atterny fees and one specific "type" of damages that the U.S. requires you to have registered the work.
You're worked up about something that applies to the U.S. right after you said "If the photographer is in the U.S.".
Yes, attorney's fees. Attorney's fees for prosecuting a copyright infringement can run around $20,000 to $40,000 USD.
Essentially, only very very large infringements are worth bothering with if you haven't registered your images.
And even for images that were not previously registered, filing a court case requires registration of the images. You can't step into a federal courtroom in the U.S. without a copyright registration from the U.S. Copyright Office. So one way or another, you're going to need to register your images -- it just makes much more sense to do it before someone steals them!