An all-caps caption declared: "We need real leadership. We need results. Let's put the U.S. back into business!"
Except, there was a problem. As Twitter users quickly pointed out, the soldiers in the bottom-right of the image were not American. They weren't even from an Allied military. They were German World War II soldiers.
Twitter sleuths set about linking the image to a stock photo of reenactors in what appears to be Nazi uniforms.
This former professor at the Naval War College appeared convinced.
And the left-of-center Web site Mother Jones made this handy GIF:
Trump's original tweet was swiftly deleted and the Trump campaign eventually pinned the error on an intern, as one journalist reported:
Trump is hardly alone in making these gaffes. Earlier this year, it appeared a video put out by Rick Perry's political action committee, touting the former Texas governor's knowledge of military history, used a stock image of a Russian warship instead of an American vessel.