I have little experience with nokia devices and I have some problem with colors on nokias (canvas's drawLine(), does not concern png).
When I test on emulator (7210) - there I can see all used colors, but on real device (6610) only the pure remain visible (eg. 255,0,0), all others become black. Is it 6610 problem? I tried to use "web safe" colors (max number of 256 limit) - no progress. (the same color rendering problem is on sony-err t610, all siemens' I checked show them correctly).