In the display shown in the pictures, each red flag represents one U.S soldier killed in Iraq, around 3,000 at the time, while each white flag represents six Iraqi civilians or soldiers killed in the war - there are over 100,000 white flags representing the estimated 655,000 dead Iraqis. That number from the Lancet study isn't accepted by everyone, but I don't want to argue the number today. Whatever it is, it's far, far too many. I can tell you this. Having seen this display on our campus, even if it's only one-to-one (which is too low) rather than six-to-one, the display is still stunning.
This is the display when it appeared at Reed college in March. Reed is is a private college north of us in Portland. These pictures don't fully reflect how much area the flags cover, but it gives you some idea (here too):
(click on pictures for larger versions)
And here are a couple of pictures from when it appeared on our campus around the same time:
In this picture, my office is off-camera on the left side of the picture. This is just part of the display - there wasn't nearly enough lawn to hold all of the flags. I can't imagine how much ground it would have covered if they hadn't used white flags to represent more than one person:
I believe this started at the University of Colorado.