Swing/AWT/SWT :: Application That Displays A Frame Containing Two Panels

I'm having trouble with this program. In my textbook it says "Write an application that displays a frame containing two panels. Each panel should contain two images (use four unique images - your choice). Fix the size of the first panel so that both of its images remain side by side. Allow the other panel to change size as needed. Experiment with the size of the window to see the images change orientation. Make sure you understand why the application behaves as it does". I successfully imported the images, but I can't find out anywhere how to allow the second panel to change size with the window.

import java.awt.*;
import javax.swing.*;
public class TwoPanels
{
public static void main(String[] args)
{
JFrame frame = new JFrame ("Embedded Images");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ImageIcon iconOne = new ImageIcon ("glove.jpg");
ImageIcon iconTwo = new ImageIcon ("cleats.jpg");
ImageIcon iconThr = new ImageIcon ("bat.jpg");
ImageIcon iconFou = new ImageIcon ("baseball.jpg");

[code]...