The blurry image apparently showing a white woman sitting on a Marshallese dock generated worldwide interest when it was included in a History Channel documentary screened last weekend.
It renewed interest in the fate of the legendary American and her navigator Fred Noonan who disappeared over the Pacific in July 1937 while attempting an around-the-world flight.
The programme suggested the undated photograph found in the National Archives in Washington showed Earhart and Noonan were captured by Japanese forces.
But military expert Matthew B. Holly said he had tracked the original image to a Japanese photographer's travelogue through Micronesia published before Earhart vanished.
Holly said that unlike the Washington photograph, the original -- available at Japan's National Diet Library Digital collection -- is dated.
He said the documents showed the photograph was taken at Jaluit Atoll in 1935 and published as part of the 111-page travelogue in 1936.
"There is no question the photo was taken in 1935," he told AFP.
Holly, an American living in Majuro, has spent decades tracking down the locations of lost US aircraft and the identities of American servicemen killed in action in the western Pacific nation.
He was sceptical about the claims made about Earhart's appearance in the photograph from the outset, citing the absence of Japanese flags and soldiers in the image.
Earhart and Noonan vanished after taking off from Lae, Papua New Guinea, and the prevailing belief is that they ran out of fuel and ditched their twin-engine Lockheed Electra in the Pacific Ocean near remote Howland Island.
There has long been an oral tradition in the Marshalls that the pair crashed on a small island in Mili Atoll and were later seen at Jaluit.
But the US-based International Group for Historic Aircraft Recovery dismisses the Marshalls theory.
It believes Earhart went down at Nikumaroro Atoll in the central Pacific nation of Kiribati and has launched several expeditions there searching for evidence.