static Image2B toImage2B(BufferedImage img) {
  ret img == null ? : new Image2B(img);
}

static Image2B toImage2B(MakesBufferedImage img) {
  if (img == null) null;
  if (img cast Image2B) ret img;
  if (img cast BWImage) ret Image2B(img);
  if (img cast IBinaryImage) ret iBinaryImageToImage2B(img);
  ret new Image2B(toBufferedImage(img));
}