static Image2B image332to2bByEqualityToColor(Color color, Image332 img) {
  if (img == null) null;
  int w = img.getWidth(), h = img.getHeight();
  Image2B i2b = new(w, h);
  int reducedColor = to332_int(color);
  for y to h: for x to w:
    if (img.get332Pixel(x, y) == reducedColor)
      i2b.setPixel(x, y);
  ret i2b;
}