Iran has been caught out in another Photoshop blunder in an effort to prove its purported stealth fighter jet is the real deal.

An Iranian state news agency released a new picture of the radar-dodging jet flying above snow-covered mountains.

Similar ... the fighter jet at the unveiling.

But the picture was immediately suspected to be fake, with the lighting on the plane and its position similar to its appearance in pictures on the ground in Tehran at the unveiling earlier this month.

President Mahmoud Ahmadinejad described it as "among the most advanced fighter jets in the world", capable of hitting ground and air targets by stealth, but experts dismissed it as a "laughable fake" which looks like a toy or mock-up model.