static BufferedImage transformBufferedImageWithSimplePixelOp(IF1_IntToInt f, BufferedImage img) {
  if (img == null) null;
  int w = img.getWidth(), h = img.getHeight();
  int[] pixels = pixelsFromBufferedImage(img);
  int[] newPixels = new[pixels.length];
  for (int i = 0; i < pixels.length; i++)
    newPixels[i] = f.get(pixels[i]);
  ret bufferedImageFromPixels(newPixels, w, h);
}

Began life as a copy of #1024727