A lot of scanned material here, but I've seen some of this guy's tutorials and he admits to using photos as textures, so he's not trying to pass off his work as scratch painted.

Wade, would the photomanipulation tag be accurate here?

It's hard to say Cons as the elements of the picture are probably sketched and painted and the photos are just overlaid to give it texture (much like texturing in 3d).

It would best fit a "matte painting" tag really.

2cents:
AFAICT, definition of "compositing" could be more accurate..

doesn't look coherent at all