static LL<BufferedImage> imageToRoughlyFixedSizeTiles_twoLevelList(BufferedImage img, int roughSize) {
  ret imageToRoughlyFixedSizeTiles_twoLevelList(img, roughSize, roughSize);
}

static LL<BufferedImage> imageToRoughlyFixedSizeTiles_twoLevelList(BufferedImage img, int roughW, int roughH) {
  int w = img.getWidth(), h = img.getHeight();
  int m = max(1, iround(doubleRatio(w, roughW)));
  int n = max(1, iround(doubleRatio(h, roughH)));
  ret imageToTiles_twoLevelList(img, m, n);
}