Two images dominate America's vision of itself at war - the heroic picture of marines raising Old Glory at Iwo Jima in 1945 and the terrible moment in Vietnam when nine-year-old Kim Phuc runs, naked and in agony, from a napalm strike. The images became iconic because they epitomised a feeling of the time: Iwo Jima represented the triumph of victory over Japan and Kim Phuc the horror as the US slipped into the cruel quagmire of Vietnam.
As the photographs of torture at Abu Ghraib emerged, I found myself on a panel judging the One World Photojournalism Award. Some images made us uncomfortable. Do photographs of wild-eyed young men with AK-47s reinforce a stereotype about war in Africa, or reveal a truth we would rather not acknowledge? Does the fact that poverty can look beautiful distort the truth? We favour photographs which tell a story that fits our world-view - the camera may not lie, but we do, to ourselves.
The Bush administration is losing the war of images in Iraq. It carefully staged the photo opportunity last May when the president strode out across the aircraft carrier Abraham Lincoln, attired in full flight suit - including parachute and water-survival kit - to declare "mission accomplished". But that image now looks ironic.
Instead, two images the administration tried to suppress may come to symbolise America in Iraq: coffins arriving at Dover Air Force Base, and a grinning Private Lynndie England, pointing mockingly at the genitals of Iraqi captives in Abu Ghraib prison.
Before the war in Iraq started, the American government made sure that the ban on taking and disseminating photographs of dead service personnel being airlifted home was strictly enforced. But it took pictures for its own record, and on 14 April a journalist called Russ Kirk won the right through the Freedom of Information Act to see the coffin pictures. After several refusals, the air force was compelled to send him a CD of 361 images of aircraft landing at the base in Delaware and the coffins being carefully borne away.
The pictures had been suppressed because of what a former Joint Chiefs of Staff chairman, General Henry Shelton, called the "Dover test" - the extent to which the American public can tolerate pictures of war dead being brought back in caskets. This administration's attempt to avoid the Dover test failed because Americans are hungry for pictures. The mainstream media in the US all carried the coffin images. The website on which they were originally published, thememoryhole.org, crashed because so many people tried to log on to it at once. But those who viewed the sombre images took different meanings. For some it was proof of the futility of war; for others a chance to honour brave soldiers who had died for their country.
Most famous photographs have a story that, to some extent, belies the meaning history bestows. The marines at Iwo Jima immortalised in Joe Rosenthal's photograph, and later in the Marine Corps Memorial at Arlington, Virginia, were not in fact the first to raise the flag on Mount Suribachi. They were a second group. They took down the small flag that had been planted at the moment the Americans reached the summit and raised a bigger one. The roll shows them planting the flag again and again, until they got it right for the camera.
Likewise, Saddam Hussein's statue wasn't spontaneously felled by freedom-loving Iraqis, but carefully pulled down by an American tank recovery vehicle. The crew had sought permission from their superiors, who had referred it back to Washington and got a thumbs-up.
The torture photographs are also staged, but in a different way. The attorney for Specialist Charles Graner, Lynndie England's boyfriend, argues that his client took pictures at the behest of military intelligence chiefs as a way of psychologically harassing the prisoners.
American and British public opinion may be far more shocked than most Iraqis at evidence of sexual torture because the images disturb a widely held view that American and British soldiers do not behave like that. But stories of rape, beatings and forced confession have been circulating in Iraq since the first prisoners were captured last year, and the photographs merely confirm what most Iraqis already believe. The pictures reinforce the sense of humiliation they feel, and the suspicion that the "coalition" and Saddam Hussein have a lot in common.
Since photography was invented, soldiers have snapped souvenirs. On one infamous web page (www.ryano.net/iraq), a smiling marine poses with two Iraqi children holding up a cardboard sign. The inscription on the original is lost in internet folklore - the website invites you to write your own message. The image can mean anything you want it to. But no government can control it.
Lindsey Hilsum is international editor of Channel 4 News