I never really knew the story of the photo until I read "Flags Of Our Fathers" (HIGHLY recommended!) I was surprised to learn that not only was it taken on the third day of a month-long campaign, but only three of the six Marines left the island alive (and of course the story of Ira Hayes after he came home is a tragedy in itself.)
Incidentally, I had always heard that there was an extra "hand" added to the flagpole on the USMC Memorial at Arlington, supposedly to represent the Hand of God or fallen comrades, but it turns out that's just an urban legend.
SN