Windows Vista's facelift is one of the core aspects in the evolution of the operating system. Vista delivers a whole new style dimension, and one of the principal visual elements is the background image. Of course that in Vista, as was the case with Windows XP, users will be able to customize their desktops according to their preferences. Vista will support images, animations and even videos (via DreamScene) as wallpapers.
However, the operating system will ship with a variety of default wallpapers. The images included in Vista are the product of amateur and professional photographers around the world. Jenny Lam, the Creative Lead on the Microsoft User Experience together with the MSE team have had the responsibility not only to design and implement icons, animations but also the general graphical experience in Windows Vista. Lam has also been responsible with selecting the images that found their way into Vista and that will eventually get on your desktop. You can access a great interview done by Robert Scoble, a former Microsoft blogger with Jenny Lam where she explains the design experiences of Windows Vista, by following this link.
The pictures included in Vista have been taken by professional photographers; in fact, Lam talks in the interview about the photo shoots in Santa Barbara and New York, but also from amateur photographers. Approximately two thirds of the wallpapers that ship with Vista have been taken from various stock websites, including Flickr, reveals Long Zheng.
Additionally, amateur photographers that have been contracted by Microsoft were also sent on photo shoot sessions in various locations around the world. Jenny Lam has analyzed in excess of 10,000 images at low resolution in order to select those that have been included into Vista. According to Raymond Chen, that is over 50GBs of images.