Como coloco uma imagem em um Applet?

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

public class Teste extends JApplet{
	
	private JButton Inserir;
	private JPanel ButtonPanel;
	private testeDois grafico;
	
	Leitor ler = new Leitor();
	
	public void init(){
		grafico = new testeDois();
		Inserir = new JButton("Inserir");
		
		ButtonPanel = new JPanel();
		ButtonPanel.setLayout (new GridLayout(1,1));
		
		ButtonHandler handler = new ButtonHandler();
		ButtonPanel.add(Inserir);
		Inserir.addActionListener(handler);
	
		Container container = getContentPane();
		container.add(ButtonPanel,BorderLayout.SOUTH);
		container.add(grafico, BorderLayout.CENTER);	
	}
	
	
	public static void main (String args[]){
		
		JFrame applicationWindow = new JFrame("Inserir nome na janela");
		applicationWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		Teste appletObject = new Teste();
		appletObject.init();
		appletObject.start();
		applicationWindow.getContentPane().add(appletObject);
		applicationWindow.setSize(600,450);
		applicationWindow.setVisible(true);
	}
	
	
		private class ButtonHandler implements ActionListener{
		public void actionPerformed (ActionEvent event){
			
			if (event.getSource()==Inserir){			
					grafico.Entrada();
					JOptionPane.showMessageDialog(null,grafico.Mostra());
				}
	     }

     }
}