Java background image question

Hi, this is my first time posting so i hope this works correctly. I've been
googling for a while now,
and i'm trying to find a way to add a background image to this panel I made.
I was able to do it by adding a button:

======================================================
//panel class

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

public class instructionsPanel extends JPanel implements ActionListener
{
    background b1;

public instructionsPanel()
{

    b1 = new background();
    b1.setBounds(0, 0, 800, 500);
    add(b1);
    b1.addBackground();

    setLayout(null);
    setSize(800, 600);
    setBackground(Color.black);

    and so on....
}

//background class

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

public class background extends JButton
{
    public background()
    {
        super();
    }

    String addBackground()
    {
        ImageIcon image1 = new ImageIcon("instructions.jpg");
        setIcon(image1);
        return "";
    }

}
======================================================

but i really don't like how the button's border flashes when the mouse
hovers
over it so i was wondering if anyone could help me with the code to just add
an
image to the background of the panel? Thanks for your time