I don't have the time right now to go explain the process in detail, but below is a screenshot of all our rejection reasons. So we have to check that the photo adheres to all of those criteria. But after a while, we usually see within a few seconds if a photo is passable or not.

Note: There are some double categories that still have to be taken care of. Dark/Underexposed are kind of the same and grainy/noise. Usually grainy is used for slides and noise for digital photos, but in time I think just noise will be sufficient. And of course Personal isn't a proper rejection reason, that's just the way to activate the writte message that we sometimes send along with a rejection.