38 private links
Download standalone codec: http://bit.ly/iTb3f4
Windows Vista introduced a new imaging stack, called Windows Imaging Component (WIC), and uses it in Windows Explorer to create thumbnails for most image file formats. 3rd parties can write their own WIC codec to support proprietary image formats such as Nikon NEF or Canon CR2 raw files and Windows Explorer is able to show thumbnails for those files when the corresponding codec is installed. Microsoft maintain a page containing links to existing codecs.
Sadly, there is no publicly available codec for the Photoshop PSD format but the newly released Microsoft Expression Blend 3 design tool (which, by the way, is nothing short of amazing for WPF and Silverlight design) includes such a codec so installing Blend 3 automatically installs the PSD codec.