static BufferedImage posterizeBufferedImage(int brightnessLevels, BufferedImage etc img) {
  PosterizeBufferedImage x = new(brightnessLevels, img);
  ret x!;
}

static BufferedImage posterizeBufferedImage(IPosterizer posterizer, BufferedImage etc img) {
  PosterizeBufferedImage x = new(posterizer, img);
  ret x!;
}

static BufferedImage posterizeBufferedImage(BufferedImage etc img, IPosterizer posterizer) {
  ret posterizeBufferedImage(posterizer, img);
}

Began life as a copy of #1033679