There are many people who may purchase an old photo if there is something really unique about that photo. This depends on the kind of photo and mysteries surrounding the photo. Similarly, many people may also be interested in buying an old painting as well. This may involve painting of a house or anything that may stir curiosity.
I believe that the photo he was talking about was his own personal photo which he hung on his wall in one of his room. I'm sure that there is no one who is going to be interested in buying someone personal photo because it doesn't hold any value for them. If I'm selling my own personal photo, are you going to buy it?