The point, you ask? There is evidence out there (I've read it and I'm looking for the source and will post it in a comment when I find it!) that indicates that looking at old pictures makes you happy. There is no way I can't smile when I look at the screen grab of Corley holding that baseball. Or when I look back through old facebook posts, or scroll through the pics on my phone when I'm standing in line at the post office, or when I get around to working on scanning our old photos that are in boxes in the basement.
My friend Jeannine goes on photo walks, and she also posts pictures of her morning coffee of Facebook. We haven't talked about it specifically, but when I've tried to do something similar, the act of finding the right angle or staging the photo helps me look for and find the beauty in settings I might overlook otherwise. So, I think this type of mindful photography, in addition to looking at old snaps, can give a body boost to their mood. In this age of digital photography and cameras on phones, it doesn't cost anything extra. Worth a shot, right?