After all component settings, create an ImageIcon object with your desired image. Using this object, create a JLabel. Add the Jalbel to the lowest LayeredPane of the JFrame. Finally, add the Jlabel to JPanel1, which is already added to JFrame.
Here is a sample code that shows the technique of setting image as background to a frame.
import javax.swing.*;public class setimage extends JFrame{ public setimage() { super("Image Setting"); JPanel imagePanel = new JPanel (); getContentPane ().add (imagePanel); addWindowListener(new java.awt.event.WindowAdapter()_{public voidwindowClosing(java.awt.event.WindowEvent e)_{ System.exit(0);}}); ((JPanel)getContentPane()).setOpaque(false); ImageIcon scenery = new ImageIcon("KERALA_SCENERY_3.JPG"); JLabel backlabel = new JLabel(scenery); getLayeredPane().add(backlabel, _new Integer(Integer.MIN_VALUE)); imagePanel.add(backlabel); pack (); } public static void main (String args[]) { new setimage().show(); }}