Yes. Facebook runs all photos thru digital recognition. If you look at the alt text for a photo in the feed it will have a string generated by their photo analy

Yes. Facebook runs all photos thru digital recognition. If you look at the alt text for a photo in the feed it will have a string generated by their photo analyzer. But that's just the front. They also use facial recognition to learn which other FB accounts are in your orbit, or make shadow profiles if they don't recognize a facial fingerprint. That way if that person ever signs up, they match the metadata from the shadow profile. This is all in service of scaling ad targeting surface area, which can be sold by the eyeball to generate massive wealth.