I got this one thanks to Rick Lowe of Blog Bahamas. It's worth a second link, I think.Liberty - Decisive Moments

What you make of a picture shows who you are, not just what the photograph depicts. Yet photographs do have an effect, as Lange suggested, in teaching people how to see. Admittedly, this may take a long time to happen. When Matthew Brady's photos of the carnage at Antietam were displayed in Washington, during the Civil War, audiences exclaimed, "How ghastly!", but did nothing: photography was too new a technology; the viewers weren't accustomed to the reality that the pictures purported to represent. When Capa's photos of men struggling and dying in the waters of Normandy appeared in Life, the American public — perhaps also not used to the raw quality of the images — took it as another just sacrifice and carried on. But when Adams' photo of the Saigon execution appeared in American and world media, sped by technology that was on the cutting edge of communications, it galvanized many people's thoughts overnight. The sense of immediacy — the sense, at least, of a sudden intrusion of unmediated, unjustified brutality — was greater than before. Eyes that had become accustomed to the contemplation of war, and had even accepted its photographic images as classical representations of reality, now looked at an image that was disturbingly hard to fit in the comfortable, classical frame.