http://www.free-legal-document.com/copyright-cease-and-desist.htmlThis one might apply more to written word, however photos (especially with identifiable people that would be unknown to the thief) would be easier to "prove" I'd think.
I tend to go for the DMCA takedown notice personally....
http://rising.blackstar.com/how-to-send-a-dmca-takedown-notice.htmlBut that goes through the ISP, not to the site owner themselves.....