static float rgbDistance(RGBImage a, RGBImage b, float maxDistance) {
  ret 1f-rgbImageSimilarityResized(a, b, 1f-maxDistance);
}

static float rgbDistance(RGBImage a, RGBImage b) {
  ret rgbDistance(a, b, 1);
}

static float rgbDistance(RGB a, RGB b) {
  ret rgbDiff(a, b);
}