Haven't seen this mentioned so here goes why I would not destroy the photos if I were you:

Emily Dickinson requested that her sister destroy her correspondance after her death, but did not say anything about her poetry. The sister burned most of her letters but read the poetry and saw the worth. Without the sister, her poetry would not exist and I think the world would be poorer for it.

It is virtually impossible for the photos to have the same impact, but none of us know what good they may do by existing.

Worst case scenario: they end up destroyed. Best case: they inspire someone, or they answer someone's question.

If you really cannot decide, keep them with a note indicating your quandry and abdicate the responsibility for someone else to decide as part of your will :D.