Well everyone's on his/her phone these days, so let's assume a second picture caught her busy with her phone. Highly doubtful a photo would be high-res enough

Well everyone's on his/her phone these days, so let's assume a second picture caught her busy with her phone. Highly doubtful a photo would be high-res enough to get text-level detail but certainly the general layout and colors of whatever she was looking at would show up. So if this led to a successful ID, she must have been looking at an app or page that is user-customizable to some extent like facebook with a unique profile and cover. If you have even a blurry image of a website, the RGB colors are still going to be pretty close so if you have some sort of way of automatically iterating through user pages on the website in question (GraphAPI), doing direct page capture to image, scaling down that image, doing the appropriate rotation, shear, etc., and then running some simple image match criteria, that "might" work. Facebook has billions of users though which surely would take more than 24 hours to iterate through, so maybe you could prune the search space by only searching friends of people claiming the high school graduation year in question.