Prisma uses deep learning algorithms to derive image processing methods that change your pictures in accordance with the style of a given artist. Other sites, like DeepArt apply these methods based on machine learning techniques, such as the one described in this article, to process photos that you upload.
The following drawing of The Thinker was obtained applying Prisma to one of my travel pictures.
The following “painting” was obtained from one image of the tall ships in Lisbon, using DeepArt.
Applying the methods takes significant computer time, and is done by Prisma remote servers. These servers have, for a while, been unable to fully cope with the demand. Other sites, like DeepArt, also take significant time to process your request.
The results are, in many cases, surprising, obscuring the line between artistic merit and computerized image processing. Recently, Google raised a significant amount of money selling computer generated art.
For more examples of computer generated art, using Prisma and DeepArt, take a look at my deep art flickr album.