I have been meaning to write this for a while now:
ROTTool (primary) or ROTTool (mirror)
It will open/view/extract any .ROT file out there (I hope) which I have found to be either DDS(DXT1 and DXT5 formats) or TGA. The DDS/TGA files are saved as the same name as the .ROT only with a different extension (obviously ).
Next version will make .ROT files as well