There are many people who believe, sometimes very strongly, that it is "cheating" to use photographs to help one to compose drawings, paintings, or other artwork. However, many highly respected (and self-respecting) artists, from the time photography became an accessible tool for artists (in the 1800s) until the present day have found it to be a great help. Eugène Delacroix (1798-1863) is one of them.
Many of Delacroix's paintings were based on photographs, requested by him to be made, of nude male and female models.
"Delacroix based a number of his figures on photographs, and himself experimented in several modes of photography, regretting that 'such a wonderful invention' had not been made earlier in his career." 150 Years of Photographic Art by Jason Edward Kaufman
The Musée national Eugène Delacroix is presently exhibiting photographs Delacroix used along with the pictures he made from them. You can see some examples if you go to the museum's website (click on the link just above).
I recommend that even if you don't understand French to look at both the French and English-language pages. You can read it in the language you prefer, but the pictures aren't all the same on both pages.
I don't know whether Delacroix used the photograph below to as a reference in painting his self-portrait within two years of the date of the photo, but I suspect not as all he had to do was look in a mirror and he would see a much more "alive" and colorful image of himself from which to paint, but seeing these two portraits together makes me realize that a painting can look more "real" than a photograph -- or you might say more "alive" -- than a photograph.
This is the first of a series of short posts on artists and photography.