It depends on what's in the photo. I lost some pets over two, three years back and never did have that many photos of them. For me the over-riding image is often of seeing them dead. That moment is seared onto my memory and can be very painful. I'm almost welling up a bit now typing it.
I also lost a pet a year-and-a-half ago, but have photos of her when she was alive, and even some movie clips. Not exactly artistic, but it's nice isn't it to have that image of someone, or something, when they're alive to call on rather than the moment of death.
I can easily see how these might help people to cope -- so many of the photos in that link capture life. It might not be for everyone, though.