running java gui on linux and windows

hi
i have a small code, and run on both linux and windows machine.

import javax.swing.*;
import java.awt.*;

public class ArdalanResim extends JFrame
{
  javax.swing.ImageIcon icon;
  Image image;

  public ArdalanResim()
  {
    icon = new ImageIcon("background.jpg");

    JPanel panel = new JPanel()
    {
      protected void paintComponent(Graphics g)
      {
        // Dispaly image at at full size
        g.drawImage(icon.getImage(), 0, 0, null);
        super.paintComponent(g);
      }
    };
    panel.setOpaque( false );
    panel.setPreferredSize( new Dimension(800, 600) );
    getContentPane().add( panel );
  }

  public static void main(String [] args)
  {
    ArdalanResim ar = new ArdalanResim();
    ar.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    ar.setSize(800, 600);
    ar.setLocationRelativeTo( null );
    ar.setVisible(true);
  }
}

on windows box, code runs fast (about in 1-2 seconds) but in linux it
takes 7 seconds to see the background.jpg. after investigating of code,
i see that the "icon = new ImageIcon("background.jpg");" causes the
delay. i tried on Debian Etch and Fedora Core 4 linux (p4 machine).
what should i do to make it faster?
thanks.