The easiest way is to use the Instagram trigger.
Give the players a tag for the game, say #photohunt and then create an Instagram trigger that fires on that tag.
You can then add to the character a "blog post" account but use your email instead. Now when the trigger fires you can send yourself an alert when a photo is uploaded to instagram with your tag.
You can also use this to award teams points etc but of course if it's important to review the photo first you'll have to add some additional logic.
All the photo URLs are given in the activity feed or else you can easily search Instagram for your tag