Load Screen Art & Concept Art
I don’t remember the name of the technique, but it’s used a lot in concept art. Basically the artist takes part of a photo (usually for the texture) and paint over it so it blends in with the rest of the drawing.
https://youtu.be/0nv2hMH3AGc?t=7m35s
Here’s a more extreme example of turning an entire photo into concept art.