Not really hard, if the damage is visible on the camera.
You go back a year and look. Damage there? If no then go back 6 months. If the damage is there then you know it's between 6 months and a year back. Rinse and repeat, binary search.
Having said that, I wouldn't store that much. A week would be all I'd want.
You are right, as soon as I posted the comment I thought of binary search. Funny how people frequenting HN think alike, maybe we have to get out more often out of our bubble.
You go back a year and look. Damage there? If no then go back 6 months. If the damage is there then you know it's between 6 months and a year back. Rinse and repeat, binary search.
Having said that, I wouldn't store that much. A week would be all I'd want.