Java SE (Java Platform, Standard Edition)

I have an image I want to be painted as the backgroudn image of a JPanel, but the paintComponent method is not being called. Here's my class:

package com.cyledawson.tworeborn;

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

public class BackgroundImage extends JPanel {
	private static final long serialVersionUID = 1L;

	public BackgroundImage() {
		super();
		setPreferredSize(new Dimension(800, 600));
		repaint(); //Added to see if paintComponent is even being launched. It's not
	}

	public void paintComponent(Graphics g) {
		JOptionPane.showMessageDialog(null, "Rawr");
		g.drawImage(new ImageIcon("terra_client_image.png").getImage(), 0, 0, 800, 600, this);
		super.paintComponents(g);
	}
}

Two notes: 1) I added a JOptionPane to check is paintComponent is being launched, and the message pane doesn't appear, and 2) As I noted, I decided to add a repaint() to the constructor in hopes it would launch the paintComponent method, but it did not.

I'm sure there's just some small mistake I'm completely overlooking, but I can find it.