How would I add a picture as a background directly to a JPanel

Is there any way to add a background without using a new JPanel?

I am making a dungeon themed minesweeper game in Java using Swing and need to have a different image as a background. My game consists of one main JFrame and the title screen, and the three difficulties as JPanels.

Adding a new Panel to add a background picture would be really difficult as it would mess with a lot of my code. I basically just want to "stick" the background to the back of the JPanel while also having it at a back layer, without covering any of the buttons.

This it how I did it. Overriding the paintComponent

import java.awt.Graphics;
import javax.swing.JPanel;
import vokabeltrainer.common.ApplicationImages;

public class TrashCanBackgroundPanel extends JPanel
{
   private static final long serialVersionUID = -7918923007938243168L;

   @Override
   public void paintComponent(Graphics g)
   {
      super.paintComponent(g);
      if (ApplicationImages.getTrashcanBackground() != null)
      {
         int x = this.getParent().getWidth() / 2 - 1000 / 2;
         int y = this.getParent().getHeight() / 2 - 620 / 2;
         g.drawImage(ApplicationImages.getTrashcanBackground(), x, y, this);
      }
   }
}

The width of the image is 1000 pixel and the height 620 pixel.

Just set the JPanels layered on top

setOpaque(false)