VTFCmd

VTFCmd is a C command line frontend for VTFLib] that can create .vtf and .vmt files from various source formats. It is similar in functionality to Valve's VTEX Source SDK utility, but offers a lot more control.

It can batch convert from image formats other than TGA, can include sub-folders in the conversion process and even generate VMT files for you.

VTFCmd is part of the VTFLib library.