static RGBImage rgbResize(RGBImage img, int w, int h) {
  if (w == img.w() && h == img.h()) ret img;
  ret new RGBImage(resizeImage(img.getBufferedImage(), w, h));
}

static RGBImage rgbResize(RGBImage img, int w) {
  int h = iround(img.h()*(double) w/img.w());
  ret rgbResize(img, w, h);
}