Ddsview image viewer source code (http://www.amnoid.de/ddsview/).
This viewer was awesome back in 2005. It's tiny, it's fast, very minimalistic but still a great commodity for my needs (game development).
An ultimate goal will be to add full dxt support. Ddsview is based on DevIL image library and it's dxt support is outdated (for instance, it won't read A8 format).
For now, I leave it almost as it is. Just added Visual Studio 2013 solution and upgraded to the latest DevIL sdk.
All credit goes to Nicolas Weber, the author of ddsview (again, see http://www.amnoid.de/ddsview/).