The GMS Graphic File Converter is a command line utility to convert images from one format to another. I built this to use for making batch conversions of textures for UT2004, but it will work with any of the supported formats.
This application requires the MW Graphics dlls to be installed. I am forbidden by license agreement to distribute the dlls, however you can download them here:
http://www.mnwright.btinternet.co.uk/download/mwgfxdll.EXE
http://www.mnwright.btinternet.co.uk/
A big thanks goes out to Martin Wright for providing these awesome dlls! 🙂