From their web site: Snap Art creates beautiful, natural media artwork in a single step. Render any image in an unlimited variety of real-world art styles including oil paint, pencil sketch, pen & ink, comics, and more. Great for stylizing photos or graphics, Snap Art works without laborious hand editing and is more versatile than Actions or brushes.
Conventional artists often use an underdrawing to outline key objects within a composition. This lightly drawn sketch serves as a guide and is usually painted or drawn over in the final composition. Similarly, Snap Art uses edge detection to discern the objects, edges, lines, and shapes of an original image. Then, using this outline, an advanced paint engine strokes and fills this outline using the brushes and colors you specify. This allows realistic reproduction of detail, but balances that realism with convincing artistry.