static BufferedImage imageWithMarkedBoxes(BufferedImage image, Cl<Rect> boxes, Color color) {
  image = cloneBufferedImage(image);
  Graphics2D g = image.createGraphics();
  g.setColor(color);
  for (r : boxes)
    drawRect(g, r.x-1, r.y-1, r.w+2, r.h+2);
  ret image;
}