Last night, Pablo made a post to the Avalon newsgroups about WindowsCodecs... To quote him directly:

We are pleased to announce that the documentation for Avalon's Windows CODECs is now posted on MSDN.

http://winfx.msdn.microsoft.com/library/default.asp?url=/library/en-us/wic/wiclh/imagingcodec/overviews/aboutwindowsimagingcodec.asp

This component of Avalon/Windows Presentation Foundation provides an extensible mechanism for supporting different imaging formats.  An application that uses these APIs can open/save images in multiple formats, both provided by Microsoft and third parties.  The individual CODECs are implemented in unmanaged code.  The imaging infrastructure can be used both from unmanaged or managed code.
http://winfx.msdn.microsoft.com/library/default.asp?url=/library/en-us/wcp_conceptual/html/4b9264c8-44ca-4f8b-b9b0-3b52ff106d35.asp

Along with an extensible image format infrastructure (including registration, discovery, and arbitration), the architecture includes extensibility for metadata formats.

An excellent overview was given at the WinHEC conference earlier in the year.
http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWPR05004_WinHEC05.ppt

This architecture provides the basis for RAW support by different companies
http://www.microsoft.com/presspass/press/2005/jun05/06-01RAWWindowsPR.mspx

In addition to imaging extensibility, the additional functionality in other areas provided by Avalon , such as text and graphics, makes Avalon the ideal platform for imaging applications, including for web based Windows applications.  A couple of additional components that complement this functionality are Longhorn/Windows Vista's Next Generation Print Path, which enables higher color fidelity for the print path, and Avalon's use of Direct3D to accelerate operations with images.

We welcome your feedback and questions, and hope to have the opportunity to chat with you about this and other Avalon/Windows Presentation Foundation technologies at the Professional Developer Conference next month in Los Angeles (http://msdn.microsoft.com/events/pdc/).

Additionally, once you install the WinFx SDK, you'll find:

  • wincodec.h and wincodecsdk.h in C:\Program Files\Microsoft SDKs\WinFX\Include
  • windowscodecs.lib in C:\Program Files\Microsoft SDKs\WinFX\Lib
    • for x64 version of this lib, use: C:\Program Files\Microsoft SDKs\WinFX\Lib\AMD64
    • for ia64 version of this libe, use C:\Program Files\Microsoft SDKs\WinFX\Lib\ia64

Stay tuned for a bunch of samples... those will be coming within the next week.