The organisation behind Wikipedia has refused to pull down a selfie taken by a macaque - arguing that the photographer who owned the camera has no rights to the image.
British nature photographer David Slater has said that he set up the picture before the monkey clicked the shutter - therefore it is his copyright, and he should be paid when people use the picture.
But Wikimedia, which runs Wikipedia, disagrees.
It argues that because animals cannot have copyright, no one owns the copyright - so it should be freely available on its Wikimedia Commons website.
"It's all based on a technicality," Mr Slater was quoted in The Times, "I own the photo but because the monkey pressed the trigger and took the photo, they're claiming the monkey owns the copyright.
"There's a lot more to copyright than who pushes the trigger on the camera.
"Nothing gives Wikimedia (the organisation that oversees the online encyclopaedia) the right to decide who owns the copyright of the image and give people permission to use it for free."
The wording on the picture that appears on the Wikimedia Commons site says: "This file is in the public domain because, as the work of a non-human animal, it has no human author in whom copyright is vested."
Mr Slater is not giving up.
He says he has lost earnings of up to $30,000 (£17,800) and wants the image taken off Wiki's huge collection of royalty-free pictures.
The image was taken in Indonesia in 2011 while Mr Slater was trying to set up the perfect image of a crested black macaque, only for the creature to come and investigate his equipment.
Wikimedia said community members will now decide if the photo should remain in the public domain, in a case which could see photographers potentially lose rights to their own selfies in future.