Does the contest guy get the right to post your work on his website forever, put them in a book or do you keep ownership of your work except for a brief time on his website? I think it would be nice if this was spelled out. What about model release from anyone pictured?
Good points. You should contact him using the bottom of the page. While you're at it, you might mention something along the lines of a watermark or something to block copy & paste.. because you can copy at this point.