On my website I say that I will do commissioned pieces from photos, but that's only to let people know I will work FROM their photos and does not mean that I COPY the photo.
A woman in Indiana contacted me to ask if I could do a painting of a place that was special to her - her now deceased Grandfather's property in FL where she'd spent many happy hours as a child/teen.  The photo she sent was dull and almost monochromatic.  After discussing the location and MOOD with her and using the colors "hidden" in the photo, I was able to create a piece that was exactly what her inner mind saw when she looked at the photo.  It was quite the challenge.
This wasn't done ON LOCATION, but I had to visit local beaches on rainy days and do some watercolor and color pencil "roughs" to catch the mood.
Sharon A