setlocation of a JButton on a drawed JFrame

[middaycrisis]

Hi guys. I've experienced a little problem, when trying to change the location of a JButton, on a g.draw'ed JFrame. setLocation doesn't seem to work. It would be great if you could help me to move this button to where I want

Here's the code:

package gui;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.util.*;
 
public class MainFrame extends JFrame {
 JPanel panel, panel2;
 JButton btn, btn2;
 JScrollPane scrollPane;
 ImageIcon icon, icon2;
 Image image;

public MainFrame(){
 
icon = new ImageIcon("src/gui/bg.jpg");
icon2 = new ImageIcon("src/gui/main_03.jpg");
 JPanel panel = new JPanel(){
 
  
  protected void paintComponent(Graphics g)
  {
  
   g.drawImage(icon.getImage(), 0, 0, null);
   super.paintComponent(g);
  }
 };
 
 panel.setOpaque( false );
 panel.setSize(500, 500) ;
 scrollPane = new JScrollPane( panel );
 getContentPane().add( scrollPane );
 
 
 
     ImageIcon img = new ImageIcon("src/gui/main_03.jpg");
     
     JButton btn = new JButton(img);
     btn.setLocation(230, 20);
     btn.setMargin(new Insets(1, 1, 1, 1));
     btn.setPreferredSize(new Dimension(256,85));
   
     panel.add(btn);
        
   
 
}
public static void main(String [] args)
{
 MainFrame frame = new MainFrame();
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 frame.setSize(500, 500);
 frame.setVisible(true);
 frame.setTitle("test");
 
}

}

Thanks for attention.