As photography and digital tools have converged, there has been a growing emphasis on modifying a photograph from its original appearance. This is not new to photography; in fact, subjective decisions are applied to an image at the moment of exposure. Artistic embellishments, such as hand tinting, have additionally altered the original image as viewed. The appearance of software such as Painter and Photoshop, coupled with the phenomenal growth of digital photography, offers photographers and artists even more expressive choices with regard to the photograph. A current trend is the interpretation of a photographic source into a traditional painted appearance. One of the basic failings I often see that lessens an interpreted photograph's visual power is the failure to destroy the image's photographic quality.
I like to think of various art forms as having a unique "vocabulary". Painting, for example, has a unique visual vocabulary. Brush strokes, canvas weave, and oil paint's color range are attributes unique to a painting. Likewise, photographs have a unique vocabulary. A key element of the photograph is sharp focus. It is very difficult from the perspective of a photographer to eliminate this key vocabulary element from an image, but it is necessary in order to imbue the image with the vocabulary of painting. You must be willing to destroy a photograph to successfully interpret it into a convincing painted result. I know this from personal experience. It is valuable to study traditional art and illustration to discover the vocabulary elements of these mediums.
Here is a photograph I took this summer at one of the Week with Monet workshops I co-taught with Darrell Chitty:

This image exhibits key elements of the photographic vocabulary: high detail, sharp focus, and narrow depth-of-field. It are these very elements that—
from the photographer's mindset—are difficult to destroy in the process of interpreting such an image into a painted result.
Here is the interpreted image:
And a detail:

I have done several things to destroy the photographic vocabulary. Notice the simplification of detail (shirt pattern, hair, skin). I've added additional painting vocabulary elements (loose brush strokes, canvas texture, "accidental" runs and drips). I also increased the saturation to move from photographic towards painting color.
Why utilize photographs to emulate traditional media? The rise of digital photography has made it absolutely simple to mix photographs with Painter's natural-media tools. Entering this brave new world are a multitude of people that don't have a background in traditional drawing and painting skills, yet yearn to creatively express themselves. The combination of tools like Painter with digital photography offer novel approaches to bridging the appearance of traditional expressive tools with photographs. These tools offer many the opportunity to express themselves in ways they may have never otherwise attempted.
Beyond, there are artists with traditional skills that find the admixture of Painter and photography as valuable allies in producing entirely new possibilities. And you can't deny the fact that the ability to undo a bad brush stroke or ink line provides an invaluable safety net in the service of production art.
Traditional media like drawing and painting aren't going away any time soon, if ever. Their long traditions and permanence ensures a robust future. A pencil, watercolors, gouache and sketchbook are still far less expensive than a laptop, tablet, and software. There is an immediacy connected with sketching that is hard to duplicate digitally. The lack of an undo (well, perhaps the eraser is the traditional undo!) demands commitment to the applied strokes. The resulting art is a record of the artist's commitment to an idea.
Painter is adept at both art from scratch and photographic interpretation. I find that combining both these means of art creation the most exciting possibility of all!
Viva la Painter!
-john