Windows Vista introduced the Windows Imaging Format, a hardware-independent format that stores images of the operating system. The premise of WIM is to make images many-to-one in nature; in other words, multiple images can be contained within one WIM file. Since Windows Vista was architected to be so modular, 95% of the base operating system can be replicated among any number of images; as a result, Microsoft itself can ship just one binary image for each processor architecture—x86 and x64—to everyone in the channel. Additionally, the sizes of each of the image files are reduced using single-instance storage techniques and enhanced compression. Further, you can create WIM files very easily for your own uses and modify them as well.
Perhaps the best usability improvement of the WIM format is the ability to edit images offline using standard file management tools like Windows Explorer. You can add files and folder to an image; for instance, instead of the painful driver addition process in Remote Installation Services, you can simply drop drivers directly into a WIM-based image and have them automatically present for future deployments. Best of all, you don't need to create independent images for each edit you make—the additions, modifications, and deletions you make can coexist in one image, reducing management burden.
