Quantization to 16 colors with different error dithering

NeuQuant 16 colors + Floyd-Steinberg
RMSE 33.999
NeuQuant 16 colors + Jarvis
RMSE 16.903
NeuQuant 16 colors + Stucki
RMSE 6.224
NeuQuant 16 colors + Sierra 3
RMSE 7.870
NeuQuant 16 colors + Sierra 2
RMSE 6.278
NeuQuant 16 colors + Sierra 42A
RMSE 5.673
NeuQuant 16 colors + Riemersma
RMSE 5.713
SColorQ 16 colors
RMSE 5.713