Oh, and because I've received the question a few times -- you CAN resubmit photos for different challenges even if you've submitted them for other challenges, but you cannot win with the same photo twice. Once you've won with a photo, that photo is out of play. If you've got a great picture of your gun at the range with your fantastic target group in it somewhere, feel free to submit it for this, and don't worry about a future accuracy challenge or anything like that... you can use it again then if you don't win this time!
Cheers,
Daniel