This tool takes an input image and creates a palettized version of it. You will get two files, a .dpf (Dusk Palette File) and a .dpt (Dusk Palettized Texture). The first being the palette, which I recommend reusing across multiple images, and the second being the indexed image, which uses the colors from the palette.
Also, dusk previously supported Alpha textures, but due to so many little platform differences I realized it is simpler and about as much work to get palettized textures working instead. As a result I suggest creating a single palette for your alpha textures, and reusing that globally.