The program I am referred to is at the bottom of the Legacy texture Tools page: https://developer.nvidia.com/legacy-texture-tools
It does not support the newer DDS types introduced with DirectX 10/11: BC5, BC6, and BC7 (the old supported formats are termed BC1,BC2, BC3). There is currently no dedicated image viewer for the DDS types, particularly BC7, used in newer games like Fallout 4 and Skyrim SE. There are Photoshop, Paint.net and Gimp plugins, but they are far too slow and cumbersome for mass previewing options.
I would be elated if WTC could be updated to support these newer codecs. I have been a loyal Nvidia customer for 10 years; please consider giving a little back in return.