Just a little OT, but I have had the opportunity to talk with a lot of painters over the last few years. It is surprising how many of them routinely use photographic tools in the creation of their artwork. Many find it useful to use PS manipulations to evaluate their works in progress. Exaggerating and diminishing color and contrast are informative about composition and visual weight. Color substitution, gradations, rubber stamping, and so on all are useful planning tools. It is far safer to experiment and feel one's way on the screen rather than on the canvas. This is a far cry from only a few decades ago when painting from photos was kind of a closet activity. And I know at least one person who gave up oils and became a digital artist from her exposure to PS.
Also interesting to see an overall all trend towards a more photographic look in recent realistic landscape painting. Brighter tonalities, distinct highlights, wide dynamic ranges, and even blown out skies are frequently seen these days, at least in Northern New Mexico galleries.