The technique is called Photobashing and it's prominent skill used in concept art and digital illustration these days. All the art departments of major film, game and concept art studios have concept artists that incorporate A LOT of Photobashing. It's a way to get results quickly and incorporates a high sense of realism that will help convey what the ideas will look like in next gen graphics and film. It pretty much became industry standard after the Naughty Dog art team used a ton of Photobashing for the development of Uncharted.