Nick Ut, the Associated Press photographer who took the iconic “Napalm Girl” photograph nearly 45 years ago during the Vietnam War, retired last week. The close of his professional career was preceded by numerous news reports recalling Mr. Ut’s famous photo of terrified children fleeing an errant napalm attack in June 1972 near Trang Bang, a village in what then was South Vietnam.

At the center of the photograph was 9-year-old Kim Phuc, her arms outstretched, her face etched in terror and pain. She was naked and badly burned. The image has become a timeless statement about war and its horrors, but it has also become embroidered by media-driven myths.

No fewer than three prominent myths have grown up around “Napalm Girl,” namely: that the photograph shows the effects of a U.S. bombing mission, that it was so evocative it swung public opinion against the war, and that it had the extraordinary effect of hastening the conflict’s end.

Calling out these myths does nothing to diminish the photograph’s emotional impact. But debunking them does free “Napalm Girl” from association with effects that are quite implausible, thus allowing a more accurate understanding of a remarkable visual artifact of a bitter war.

No myth of the “Napalm Girl” is more corrosive than the notion that Mr. Ut’s photograph captured a destructive napalm strike by U.S. warplanes. Such claims have surfaced periodically over the years. In recent months, the Los Angeles Times, USA Today, Forbes and the U.K.’s The Independent are among the news outlets to have asserted American responsibility for the napalm attack.

But as news reports at the time made clear (among them a front-page article June 9, 1972, in The Baltimore Sun), the napalm bombing was carried out by a South Vietnamese Air Force pilot flying a propeller-driven, American-made A-1 Skyraider. The attack was an attempt to roust North Vietnamese units from positions near Trang Bang. The forces engaged there in early June 1972 were all Vietnamese.

A related myth is that “Napalm Girl” packed such a visceral punch that it swung U.S. public opinion against the war.

But in fact, public opinion had turned against the war years earlier, as a Gallup poll detected in October 1967. Forty-six percent of respondents to the survey said it had been a mistake to have sent troops to Vietnam; 44 percent said then it had not been a mistake. When Gallup first asked the question in 1965, 24 percent of respondents said it had been a mistake to send troops to Vietnam; 61 percent said it had not.

By May 1971 — more than a year before Mr. Ut took the photograph — 61 percent of respondents said it had been a mistake to send U.S. troops to Vietnam; 28 percent said it had not.

Nor did “Napalm Girl” hasten the war’s end, a myth that even AP has embraced. In an article in 2012, the news agency said the photograph “communicated the horrors of the Vietnam War in a way words could never describe, helping to end one of the most divisive wars in American history.”

The war did not end until April 1975, when North Vietnam’s military conquered the South.

For most American ground forces, though, the conflict had been winding down long before the aerial attack at Trang Bang. Under a policy of “Vietnamization,” the administration of President Richard Nixon shifted the burden of fighting to the South Vietnamese while dramatically reducing the U.S. combat presence.

American strength in Vietnam fell steadily from a peak of 543,00 troops in April 1969 to 60,000 in early June 1972. By then, nearly all U.S. combat units had been removed from Vietnam. The draw-down of U.S. forces was neither accelerated nor otherwise influenced by the publication of “Napalm Girl.”

What, then, explains the persistence of these media myths? From where do they spring?

An inclination to indict the morality of the U.S. war effort in Vietnam helps explain the notion that U.S. warplanes dropped the napalm at Trang Bang.

The photograph’s timelessness also contributes to the tenacity of these myths: Because “Napalm Girl” is so evocative, it is easy to believe that it must have exerted powerful and sweeping effects when it was published. Assigning mythical properties to the photograph has become a way to confirm its exceptionality.

W. Joseph Campbell is a professor at American University in Washington, D.C. He is the author of six books, including a recently published second edition of “Getting It Wrong” (University of California Press), which is about media-driven myths. Twitter: @wjosephcampbell.