Pictures of Sadness

Me and my family were looking at pictures yesterday and family members that actually knew some of the people in the pictures had basically forgot about them.
Pictures can be taken and saved, but it doesn't mean you'll remember the people in them or still have anything to do with them. Does it?
I'm not really sure with what I'm trying to say, but it just strikes me as odd I guess that all that is possible no matter how much we may try to forget.
Which brings me to this:
I've come across pictures that have had pieces cut out and torn to remove someone else. As much as we want to forget the things that have tainted our good memories with sadness it still saddens us. I think it's because we know who or what it was in the picture.
I can't exactly put my finger on all the reasons it makes us sad, but I can tell you that it did make me sad. (Sorry, but this is the closest quote I could find to match what I was talking about)

“We never taste happiness in perfection, our most fortunate successes are mixed with sadness.” - Pierre Corneille