Image in Frame

/**
*
* @author akhtar
*/

import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main extends JFrame
{
Main()
{
add(new ContentPanel());
setSize(500, 300);

setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
Main jrframe = new Main();
jrframe.setVisible(true);
}
}
class ContentPanel extends JPanel
{
Image bgimage = null;
ContentPanel()
{
MediaTracker mt = new MediaTracker(this);
bgimage = Toolkit.getDefaultToolkit().getImage("a.jpg");
mt.addImage(bgimage, 0);
try
{
mt.waitForAll();
}
catch(Exception ex)
{
System.out.println(ex);
}
}
public void paintComponent(Graphics g)
{
g.drawImage(bgimage, 1, 1, null);
}
}


simply put a image named a.jpg in the same directory of your program.
plz comment to make its better.....