They are photos of iconic moments but whether certain pictures are true snapshots or false images has overshadowed many of them for decades, reports CBS News correspondent Michelle Miller.
That's the mystery surrounding Robert Capa's "Falling Soldier." An analysis of the photo conducted earlier this year has reignited a decades-long debate about whether the image - supposedly of a man being shot during the Spanish Civil War - was staged. Director of the International Center of Photography, Willis Hartshorn says it's a debate that may never truly be solved.
"You want the negative of the falling soldier, we don't have that negative, you want the negative of the shot after the falling soldier we don't have that negative," Hartshorn says.
Photography historian Philip Gefter says the debate over photo-editing dates back to at least 1860 and a specific photo: When Abraham Lincoln's head was attached to John C. Calhoun's body. Calhoun's pose was thought to be more presidential.
"That's kind of pre-Photoshop, that is what Photoshop is today," Gefter says.
Famous Civil War photographers like Alexander Gardner even repositioned dead soldiers. Gefter says this practice was routine because there were no real photo-journalism standards.
"You expect what you see in a newspaper or magazine to be what actually took place, but this was pre-journalism," Gefter says.
But even in the 1950s, staging was commonplace -- like having an "American Girl in Italy" pass a group of Italian men twice. Even the famous "Kiss at the Hotel de Ville" was staged. Life Magazine reported it as a spontaneous moment in Paris, but actually two models posed for the camera.
"This picture is a beautifully crafted lie," Gefter says.
Photographers like Lewis Hine altered reality, too. He re-shot one image after asking the worker to zip up his pants.
"Is this a false image? No," Gefter says. "This is the work that this man did, it's just he was posing for the camera."
As photo technology evolved, the editing became more sophisticated.
Remember the scenes from Kent State? Student photographer John Filo eventually won the Pulitzer Prize for one photo -- but Life Magazine published an altered version -- editing out a pole behind the screaming girl.
Probably the most rumor-plagued photo has been the one of the Marines at Iwo Jima.
"Those rumors are based on a misunderstanding," Gefter says.
Photographer Joe Rosenthal admitted he staged a photo on the hill during a radio interview. But a Time reporter assumed he was talking about the memorable flag planting image.
"Our expectation of a photograph is that it's real, because it looks like the way we see the world," Gefter says.
It's an expectation that will continue to fuel the debate. Because images can be influential in framing moments in history -- whether the photos are true or not.