NVIDIA just released a new version of their free Texture Tools. Texture Tools is a handy tool for compressing textures, generating MIP, normal and cube maps and more. It also includes a Photoshop plugin and can be driven from a command line interface.
Details from the NVIDIA developer site:
Today, we’re releasing the free NVIDIA Texture Tools Exporter, the new version of our DDS texture compression tool, available both as a standalone application and as a plugin for Adobe Photoshop.
This all-new release adds support for modern, CUDA-accelerated Texture Tools 3.0 compression (including ASTC, BC7, and BC6s), support for more than 130 DXGI and ASTC formats, linear-space, slope-space, and pre-multiplied alpha mipmapping, command-line and Photoshop automation, and a unified user interface.