Honestly, I think that the users of this forum are already wise to scams like this, but, seriously:
"By entering the Contest, each contestant grants to Sponsor an exclusive, royalty-free
and irrevocable right and license to publish, print, edit or otherwise use the contestant’s submitted
entry, in whole or in part, for any purpose and in any manner or media (including, without
limitation, the Internet) throughout the world in perpetuity, and to license others to do so, all without limitation or further compensation."
So, you gain a permanent, royalty-free exclusive license to unpublished work for free, even if not chosen for publication, and 90% of the photos chosen for publication receive nothing, the 'winner' loses all rights to his photo. . . That's not a contest, it is probably as legally far as youc an go without running foul of fraud legislation.