Advances in machine vision will let employers, governments, and advertisers spot you in photos and know exactly what you’re doing in them. All of us have become used to uploading photos and videos safe in the knowledge that we have privacy through obscurity, but as data-mining images becomes easy, they could come back to haunt us. I’ve been able to move on from my youthful missteps, but it could have been different if all the landlords, potential employers, and bureaucrats I’ve dealt with since then could have summoned photographic evidence of them all at the touch of a button.