We all know about Abu Ghraib, the prison in Iraq where American soldiers tortured their captives and documented it all with photos that will be forever burned in our memories. But imagine if those photos had never been taken. We'd never know about that disgraceful treatment -- forcing men to pose in sexual positions with each other, piling them into a pyramid of naked bodies, and of course, covering one in a black shroud, tying supposedly electrically charged wires around his fingers, and making him stand for hours-on-end atop a cardboard box. And the soldiers would likely have gone unpunished.

Thanks to those photographs, we learned some necessary facts about the US military's treatment of Iraqi prisoners. But we didn't learn as much as we thought.

This is the message behind Errol Morris's new documentary, Standard Operating Procedure. The film doesn't exactly tell us anything we don't already know. We know they were taken by American soldiers who were complicit in the torture. We know that some of the soldiers involved were more instrumental than others, while others were young, scared, or otherwise too overwhelmed by the situation to do anything about it. We know that the treatment they depict is horrendous. And we know that America's public image was tarnished by them, revealing something many Americans might have trouble reckoning with: that not all US troops are knights in shining armor, fighting for justice and democracy, freeing Iraqis from a tyrannical past. In short, we're not all "Good Americans" and this war is out of control.

But they also allowed for certain presumptions. In an interview, Errol Morris said that "the left looks at the picures, and what do they mean? They mean this is the hand of Cheney and Rumsfeld, who created policies and forced these kids to do what they did. The right thinks Animal House on the night shift."

So Morris and his crew set out to unravel the mystery a little further, a skill the 60-year-old documentarian has sharpened over the past three decades through films like The Thin Blue Line and The Fog of War, which received an Oscar in 2004. What this film reveals is less about what happened, and more about what else happened -- that is, what occured outside the frame, just out of view. The investigation proves that those horrible events were anything but black-and-white.

As Morris writes on his Website, the photographs were both an expose and a cover-up. An expose because they told the world what happened at Abu Ghraib, and a cover-up because they convinced the public and the media alike that they told the whole story.

Through first-hand testimony by those involved -- including Lyndie England, the then-21 year-old private, and Sabrina Harman, whose "thumbs-up" pose with the prisoners led us to shake our heads in disgust -- Morris's film attempts to correct some of these presumptions.

Hopefully, the film's legacy will be to inspire critical inquiry into how the media presents information in the future, no matter how solid the evidence might seem.