Como adicionar imagem em um JPanel

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.JPanel;

/**
 * A panel that contains a background image. 
 * The background image is automatically sized to fit in the panel.
 */
public class JImagePanel extends JPanel
{
    BufferedImage background = null;
    
    /** Creates a new panel with the given background image.
      * @param img The background image. */
    public JImagePanel(BufferedImage img)
    {
        if (img == null)
            throw new NullPointerException("Buffered image cannot be null!");
        this.background = img;
    }

    /** Creates a new panel with the given background image.
      * @param img The background image. 
      * @throws IOException, if the image file is not found.
      */
    public JImagePanel(File imgSrc) throws IOException
    {
        this(ImageIO.read(imgSrc));
    }

    /** Creates a new panel with the given background image.
      * @param img The background image. 
      * @throws IOException, if the image file is not found.
      */
    public JImagePanel(String fileName) throws IOException
    {
        this(new File(fileName));
    }
    
    @Override
    protected void paintComponent(Graphics g)
    {        
	super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g.create();
        g2d.drawImage(background, 0, 0, this.getWidth(), this.getHeight(), null);
        g2d.dispose();        
    }    
}