Pioneer - thanks for your replies. You're one of the few people who've responded thoughtfully.
To pick up on your earlier post, photographs do not desensitise us to violence per se; rather, the result of seeing too many photographs of violence too often is that documentary images of war lose their impact, and that is the concern. The argument is not that photographs aren't evidence of violence and don't affect people and public opinion but that we become too used to them. I believe that photographs of war and suffering today have less power than in the heyday of photojournalism in the second half of the 20th century, simply because we've become too used to them. Think of all the iconic photographs from the 1960s-1970s, then consider the paucity of significant images in, say, the past two decades (and it's not as if nothing newsworthy has happened!); the type of images that used to affect us have today become part of the background noise of our culture.
Regarding voyeurism and photographs, surely you would have to agree that if we look at, say, the Abu Ghraib Prison photos, we are perpetuating abuse in a way? What do you think the detainees in the images feel about people staring at them being degraded for years on end? Photographs are far more a part of reality than, say, the words in a newspaper report, and impact those within them more surely. Photographs are far more intrusive than text; they're not mere interpretations of the world like a painting. We must not forget that when we look at a documentary photo, we are looking at something that happened, and perhaps still is.
Do we have a right to continue to humiliate these detainees long after the event by continuing to circulate these photographs? And if we keep showing them, will these images lose their power? I used to share a house with someone who attended accident victims, and recall him blithely talking about amputating limbs whilst eating dinner (thanks, Tony!) - but just a year before, when he started working at the hospital, he used to come home pale and shaking.
On the other hand - as you say - if we don't show these photographs, then there's the real danger of the event being forgotten, of people not knowing. Perhaps, as Sontag says, their circulation should be mediated in some way. Not easy questions. There are several books that attempt to answer them, one of the most recent being Julian Stallabrass's, "Memory of Fire: Images of War and The War of Images". As has been pointed out in this thread, two decades after "On Photography", Sontag gave a more considered second take on violence and photography in "Regarding the Pain of Others", mediating some of her more strident earlier opinions.
Photographs are more... intrusive... than other kinds of media. They're not at all like other pictures, and have power and authority unique to them that goes far beyond a surface composition of form, tone and colour. And it is these qualities that photography theory attempts to understand.
