The NVIDIA Texture Tools is a collection of image processing and texture manipulation tools, designed to be integrated in game tools and asset conditioning pipelines. The primary features of the library are mipmap and normal map generation, format conversion and DXT compression. DXT compression is based on Simon Brown's squish library. The library also contains an alternative GPU-accelerated compressor that uses CUDA and is one order of magnitude faster.
Wiki with command-line tool and API documentation available here.
The MIT-licensed source code for our Texture Tools 2 is available here.