[crossfire] Indexed PNGS, was Re: Protocol & compression.

[temitchell at sympatico.ca]

When making images for crossfire I tried to stick with indexed pngs and use the smallest colour size possible (usually 16-32 colours).  This made the files much smaller than the same images in rgb format and usually there was no noticable differences since the graphics were too small for much shading or graduation.

A lot of the indexed png images do not use the full 256 colours.  Some are saved with smaller index table and some aren't.  I suspect the ones that can be compressed are in the latter category.