Until now, Windows Explorer did not have native support for RAW images and could not generate thumbnail images.
“Dealing with raw images on Windows hasn't always been easy,” stated Group Program Manager for Windows Live, Brad Weed. RAW files are simply digital negatives that allow for much more data than a JPG and offers greater control over what the final image will look like.
Photographers will no longer have to rely on a third-party software such as Adobe Bridge to preview RAW images. The Codec Pack is free and is available for 32bit and 64bit versions of Windows Vista and Windows 7.