animated selection sort on brightness of pixels of an image

Question

Hi in this code in java I want to sort the pixels of the image through their brightness in java by using inversed selection sort however there is no update in the result image. how can i make it work?

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

public class Sort {
    private BufferedImage image;
    private int rgb;
    int iterationCount ;
    public Sort(BufferedImage image){
        this.image = image;
        this.iterationCount = 0;
    }
    public void ChainListWithBrightness(BufferedImage image) {
        double[][] points = new double[image.getWidth()][image.getHeight()];
        for (int i = 0; i < image.getWidth(); i++) {
            for (int j = 0; j < image.getHeight(); j++) {
                rgb = image.getRGB(i, j);
                points[i][j] = pixelBrightness(rgb);
            }
        }
        diagonalListingOfPoints(points);
    }

    private void diagonalListingOfPoints(double[][] points) {
        ArrayList<Double> diagonalBrightnessValues = new ArrayList<>();
        for (int m = 0; m < image.getWidth() + image.getHeight() - 1; m++) {
            int i = Math.min(0, image.getWidth() - 1);
            int j = Math.max(0, m - image.getWidth() + 1);
            while (i >= 0 && j < image.getHeight()) {
                diagonalBrightnessValues.add(points[i][j]);
                i--;
                j++;
            }
        }
        selectionSort(diagonalBrightnessValues);

        // Apply sorted brightness values back to the image
        int index = 0;
        for (int m = 0; m < image.getWidth() + image.getHeight() - 1; m++) {
            int i = Math.min(0, image.getWidth() - 1);
            int j = Math.max(0, m - image.getWidth() + 1);
            while (i >= 0 && j < image.getHeight()) {
                points[i][j] = diagonalBrightnessValues.get(index);
                index++;
                i--;
                j++;
            }
            //iterationCount++;
        }
        for (int i = 0; i < image.getWidth(); i++) {
            for (int j = 0; j < image.getHeight(); j++) {
                Color oldColor = new Color(image.getRGB(i, j));
                int red = (int) points[i][j];
                int green = (int) points[i][j];
                int blue = (int) points[i][j];
                Color newColor = new Color(red, green, blue);
                image.setRGB(i, j, newColor.getRGB());
            }
        }
        iterationCount++;
    }

public static void main(String[] args) throws IOException {
    BufferedImage img = ImageIO.read(new File("C:\\Users\\jafar\\Documents\\semester3\\cs102-1\\Lab\\lab6\\skyy.jpg"));
    Sort sort = new Sort(img);
    sort.ChainListWithBrightness(img);
    System.out.println("Sorting completed with " + sort.iterationCount + " iterations.");

    // Display the sorted image
    showImage(sort.image);
}

    private static void showImage(BufferedImage image) {
        JFrame frame = new JFrame("Sorted Image");
        ImageIcon icon = new ImageIcon(image);
        JLabel label = new JLabel(icon);
        frame.add(label);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}

I was expecting an image which is sorted through its pixel brightness but the result is displaying the original image again to me