The one that got me was some people at a beach in black and white.
The gay marriage one I couldn't put a date, but noticed a flip phone on the picture so I just guessed the highest number before iPhone release year and wasn't too bad.
The disco scene was clearly a 70s Pic so I just guessed smack in the middle of the decade.
The beach black and white I was the most off. I faintly remember that it was a big discussion point during the 20s that women should be allowed to wear "revealing" swimsuits,so again I went for a year in the decade. I was off
I didn't really recognize any of the current events - or anything at all - I just ... kind of knew ...
In fact, it had less to do with the actual content of the photo than the qualities of the photo itself ... I sort of felt like photos looked like that around 1990 ... and I was right.