sbool imagesIdentical(BufferedImage img1, BufferedImage img2) {
  if (img1 == img2) true;
  if (img1 == null) ret img2 == null;
  if (img2 == null) false;
  
  int w = img1.getWidth(), h = img1.getHeight();
  if (w != img2.getWidth() || h != img2.getHeight()) false;
  
  var gp1 = grabbableIntPixels_fastOrSlow(img1);
  var gp2 = grabbableIntPixels_fastOrSlow(img2);

  int[] pixels1 = gp1.data, pixels2 = gp2.data;
  int scanlineExtra1 = gp1.scanlineStride-w;
  int scanlineExtra2 = gp2.scanlineStride-w;
  int i1 = gp1.offset, i2 = gp2.offset;

  var ping = pingSource();
  for y to h: {
    for x to w:
      if (pixels1[i1++] != pixels2[i2++])
        false;

    i1 += scanlineExtra1;
    i2 += scanlineExtra2;
    ping?!;
  }

  true;
}