http://www.whois.net/
Type in the bare URL and you get all the contact details for the person who owns the domian name.
(although, you only get what they've written in when they register the domain,
http://www.whois.net/whois/the-digital-picture.com has all the fields left blank so we can't get Bryan's address and nick all his camera gear, he's obviously smart enough there...)
And of course that only works if the person who stole the image is also the one who owns the domain name, like if it's a *.blogspot.com or something it's useless. But it's a start.