In her 1977 collection of essays, “On Photography,” Susan Sontag identified a feeling of helpless voyeurism that comes over us as we look at photographs of people in the midst of conflict. She also wrote about how repeatedly seeing such images could anesthetize the vision and deaden the conscience. Sontag understood photographs of conflict to be making a utilitarian argument — that they could bring us into a state of productive shock — and showed that they seldom did what they claimed, or hoped, to do.