static BufferedImage toBufferedImageOpt(O o) {
  if (o instanceof BufferedImage) ret (BufferedImage) o;
  if (o instanceof MakesBufferedImage)
    ret o/MakesBufferedImage.getBufferedImage();
  S c = getClassName(o);
  if (eq(c, "main$PNGFile"))
    ret (BufferedImage) call(o, "getImage");
  null;
}