I shudder to think of DRM being applied to still photos, but the concept is nothing new. Film photographers have used all kinds of techniques to keep proofs from being stored or copied.
Hight res digital images now have watermarks, some visible, unless you buy the rights. The companies that make watermarking software charge a fee per image. If Microsoft gets into this business, it will just be another competetor.
Microsoft is already in the general industry. Bill Gates founded Corbis, the #2 stock image company, which controls the Bettman and UPI image archives, among others.