not all previous relationships end badly so someone might not feel the need to destroy old photos. fact is that the person was still a part of their life and memories, but that is all it is. As long as A) they are not pics of the 2 of them making out everywhere B) they are not displayed all over the house or bedroom (as you say they aren't) then no big deal.
Yeah I would have to agree, I mean in many cases your past relationships and people you were involved to some extent are part of who you are and as such I don't see just having them around being that big a deal as long as they don't make a big thing about those pictures.
wow. how would you know? jk but seriously. i agree. sometimes even if things didn't end badly you gotta chuck some stuff because it's painful to have around. clean up your environment for a positive change, so that memories don't leave you in the dumps or craving an impossible renewal. theres a balance. sadly most people aren't balanced--after a relationship who's REALLY feeling balanced? i know most people will either keep it all or chuck it all. few people even care balance it.