piatkow - 8:53 am on Apr 6, 2009 (gmt 0)

First check if he has actually copied the images or has just hotlinked them.
Second look at the images very carefully to see if they are your images. (I was nearly caught by this once when somebody else had published a picture of the same subject from exactly the same position)
Third make sure that you can prove that you are the owner of the images. Do you have negatives? Do you have soft copies with earlier date stamps? Have they trimmed off a watermark showing your copyright?

Follow up action depends on the jurisdiction that you are in, the jurisdiction that the copier is in and the nature of the subject.

Typically
Contact Google - IIRC there is a process for registering complaints like this but I can't remember the details.
contact the site owner requesting that they either take down the pics (or if you prefer to acknowledge you as copyright owner with a link)
If that does not get a response then complain to the hosting provider.
If no joy there then repeat the complaints in writing and use whatever process your local postal service has for having delivery formally acknowledged. You may want to take legal advice over wording.
Finally go to your lawyer.

If the pictures are hotlinked then rename the files.