Artist David Hockney, who created photo collage works in the 1980s, has said digital manipulation will kill off photography as an art form.
Hockney was ninth in a top 10 of best-selling living artists with sales of £23.7m
Hockney told the Guardian newspaper that photographs can be so easily altered these days that they can no longer be seen as factual or true.
He also said art photography was "dull" and that it was inferior to painting.
But Russell Roberts of the National Museum of Photography, Film and TV said Hockney's argument was "simplistic".
Hockney also said war photography was cast in doubt due to digital advancement.
He cited the case during the Iraq war when the Los Angeles Times sacked a photographer for superimposing two images to make them more powerful.
"You've no need to believe a photograph made after a certain date because it won't be made the way Cartier-Bresson made his. We know he didn't crop them - he was the master of truthful photography," Hockney told the Guardian.
"But you can't have a photographer like that again because we know photographs can be made in different ways," he added.
Hockney hopes that painting will gain in standing as more people realise the camera can be made to lie.
The artist said his sister's use of digital photography had brought home the effect manipulation was having.
"She's just gone mad with the digital camera and the computer - move anything about. She doesn't worry about whether it's authentic or not; she's just making pictures."
Hockney told The Guardian that no photograph or video could ever capture the tenderness of a Rembrandt drawing showing a young family teaching a child to walk.
Eamonn McCabe, a former picture editor at The Guardian, admitted the general perception of photography as truth had been lost.
But he said this did not take anything away from good photography.
"To say that photography is dead is faintly ludicrous. It would be better to say that you should be wary of everything."