found this in the bungie forums

"Hi all,

One of the several servers that accepts your screenshot uploads was receiving them correctly, but was being sneaky and pretending to the database that it didn't have anything new to store. I had a nice friendly chat with said server and it has decided to cooperate and relinquish your many screenshots that it had been hoarding. These were finally processed over the past two days. As of right now, all old and new screenshots that our servers received are processed - we're caught up.

That said, we're still looking into another possible problem where a much smaller portion of screenshots are not making it through the system for some other unknown reason. But you can keep uploading screenshots without dealing with the really high "failure" (not really - they're there now) rate you've recently seen - you should have much better success now.

Thanks for your patience!"