Many artists these days paint from photographs or trace projected images onto their substrate - techniques which are frequently dismissed as "cheating." As an artist who garners source material from the Internet and personal photographs, I have often been asked my opinion in this matter. Here it is:
I have seen portraits/still lifes/landscapes etc painted from live subject matter that are derivative and staid, and I've seen paintings that were obviously traced from projections that are vital and imaginative. And vice versa. Ultimately, it doesn't matter to me what technique the artist uses, as long as the final painting is successful.
Furthermore, devices like Photoshop, projectors, photographs, and The Internet are reflections of the times we are living in. To expect that these methods not enter contemporary artwork is completely regressive.
To read an in depth critique on this subject visit this ARTnews link