well painting large works is easier than doing small ones, same with photoshop they use a tablet which makes it easy, they also use a photograph and paint over is so that you dot see where it came from, it may look good but to what limit?
Yes I know with digital painting but I mean photo restoring with airbrush. It gives you a lot more flexibility to repair the photo. Where cloning and healing tool are limited if an entire arm is missing or something. Faces are really difficult without using an airbrush. Here are mine here [link] It was just a 1 time attempt and I did all in a day or 2. Never did another one since.