Colocar uma Imagem (Background) no JFrame

package panel;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class MyPanel extends JPanel {

    private Image image;

    public MyPanel() {
        this.initialize();
    }

    protected void initialize() {
        this.image = this.getImage("background.gif");
        
        this.setLayout(new BorderLayout());
    }

    public Image getImage(String path) {
        URL imageURL = getClass().getResource(path);
        if (imageURL == null)
            return null;

        return new ImageIcon(imageURL).getImage();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Dimension dDesktop = this.getSize();

        double width = dDesktop.getWidth();
        double height = dDesktop.getHeight();

        Image background = new ImageIcon(this.image.getScaledInstance(
                (int) width, (int) height, 1)).getImage();

        g.drawImage(background, 0, 0, this);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new MyPanel());
        frame.setSize(400, 300);
        frame.setVisible(true);
    }
}

desktop = new JDesktopPane(){
          Image im = (new ImageIcon("suaImagem.jpg")).getImage(); 
          public void paintComponent(Graphics g){        
           g.drawImage(im,0,0,this);            }
                                      };