I think this is key. Figuring out a name from a photo with no additional data would give a high probability of incorrect identification. But any metadata atta

I think this is key. Figuring out a name from a photo with no additional data would give a high probability of incorrect identification. But any metadata attached to the photos could be useful. Date the photo was taken. Where the photo was taken (e.g. the annual family reunion in SmallTown, Illinois) Photographer. They're likely taking photos of the same general set of people or in the same geographic area. Time+location of other similar photos. Back in the days of the civil war, it wouldn't be possible for someone to be in to locations 1,000 miles apart in 2 days. Side note: I recently saw a video from ~1910 in New York City. Everybody in the video had a similar physical build and would make the "average" person today look fat. I wonder how this would affect the confidence of photo grouping? Overall, did people look more homogeneous back then?