Here's an interesting update to a photo contest currently being run....and it's possible copyright implications.
In a nutshell, it allowed entrants to find any photo (perhaps yours) on the web...then submit it to the contest in an effort to win a prize.

Apologies were rec'd from Microsoft and contest prize sponsers...further, Microsoft has stated it will obtain rights to used photos.

http://www.pro-imaging.org/content/view/374/173/

In youth, we learn....with age, we understand.