We have a new set of tools for image processing in the Simutrans community, that complements the Shades tool.

It’s recomended for those who work with special colors directly within the XCF file (gimp native image format). It offers several functions like selecting, removing, repairing, lightening, darkening and converting special colors. It works with six different groups of special colors, the basic in Simutrans: Non-darkening greys, Windows, Primary player colors, Secondary player colors, Lights and Transparency.

You can download it here. More details at the Simutrans International Forum