A photograph of a recent Iranian missile test was apparently doctored to show a fourth missile firing from a desert testing range, analysts and photographic experts have said.

The image was posted on Wednesday on a website run by Iran's Revolutionary Guards and was quickly circulated by news agencies, appearing on front pages of hundreds of newspapers and websites – including this one –around the world.

The scene was described as part of military manoeuvres in which nine missiles were test fired, including an enhanced version of the Shahab-3 missile.

But a subsequent version of what is apparently the same image has since emerged, showing just three missiles lifting off and one remaining on its launcher.

That has led some analysts to speculate that at least one of the missiles involved in the test failed to fire.

Iranian officials have made no comment on the photo.

The missile test was part of a show of force by Iran, drawing sharp responses from both the US and Israel amid escalating tensions over Iran's alleged nuclear weapons programme.

Smoke trail

Photo experts say the fourth missile appears to have been added digitally, pointing to similarities in the smoke trail and dust clouds from two of the other missiles.

The photo arm of the French news agency AFP, which was one of the first to release the original image, said on Thursday the picture was "apparently digitally altered to replace the grounded missile and launcher with a fourth successfully launched missile".

Mark Fitzpatrick of the London-based International Institute for Strategic Studies told AFP: "It very much does appear that Iran doctored the photo to cover up what apparently was a misfiring of one of the missiles."

"The whole purpose of this testing was to send a signal, so Iran both exaggerated the capabilities of the missile in their prose and apparently doctored the photos as well," he said.

Gerard Issert, a technician at Granon, one of the largest photo laboratories in Paris, also told the agency that the photo was a "doctored image".

"Although the missiles weren't all equidistant from the camera, they're the same size in the picture," Issert said.