Alpha channel
Developer/verb/Change_Alpha() for(var/r = 0 to 255) for(var/g = 0 to 255) for(var/b = 0 to 255) src.icon.SwapColors(rgb(r,g,b,255),rgb(r,g,b,150)0
icon.MapColors()
icon.SwapColors() + rgb() with alpha parameter defined
Example (not tested):
There may be an easier way I think...