2 swing questions: JScrollPane and displaying pictures

Question

I'm building a GUI for a toy application I have written, I have two questions:
1-The main window is inherited from JFrame, There is a JTabbedPane attached to it, and a JPanel as the first tab of the tabbed pane. There are so many jcomponents in this JPanel, this makes it too big for small resolution computers (below 1024 * 768), I would like to add this JPanel to a JScrollPane to make it behave like a text area, I've done it but it didn't work, obviously there is something I'm missing.
2-My application calls another program to create some images at runtime which will be displayed in the other tabs, after calling the program and creating the image, I get the filename of the image. What is the best way to display this image?
I have tried JLabel's but they don't update their pictures for some reason after it has been changed.
Thanx in advance.

Answer 1

Updated and tested code, hopefully this will help.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
public class ImagePanel extends JPanel {
  private String imageFilename = null;
  private Image image = null;
  private Toolkit toolkit = null;
  public ImagePanel() {
    super();
    toolkit = Toolkit.getDefaultToolkit();
  public void setImageFilename(String filename) {
    imageFilename = filename;
    try {
      image = toolkit.createImage(imageFilename);
      setPreferredSize(new Dimension(image.getWidth(this), image.getHeight(this)));
      repaint();
    } catch (Exception e) {
      e.printStackTrace();
      imageFilename = null;
      image = null;
  public Dimension getPreferredSize() {
       if (image == null) return new Dimension(0, 0);
       else return new Dimension(image.getWidth(this), image.getHeight(this));
  protected void paintComponent(Graphics g) {
       Insets insets = getInsets();
       g.setColor(Color.white);
       g.fillRect(0,0, insets.left + getWidth(), insets.top + getHeight());
    if (image != null) {
      g.drawImage(image, insets.top, insets.left, this);
  public void reloadImage() {
       if (imageFilename != null) {
      try {
        image = toolkit.createImage(imageFilename);
        repaint();
      } catch (Exception e) {
        imageFilename = null;
        image = null;
  public static void main(String args[]) {
       JFrame frame = new JFrame();
       frame.addWindowListener(
            new WindowAdapter() {
                 public void windowClosing(WindowEvent we) {
                      System.exit(0);     
       frame.setSize(600, 400);
       JPanel parentPanel = new JPanel();
       parentPanel.setLayout(new GridLayout(1,1));
       JTabbedPane tabPane = new JTabbedPane();
       ImagePanel imagePanel = new ImagePanel();
       JScrollPane scrollPane = new JScrollPane(imagePanel);
       imagePanel.setImageFilename("C:\\dell\\drivers\\R27748\\mrmfiles\\image015.jpg");
       parentPanel.add(scrollPane);
       tabPane.addTab("Tab 1", parentPanel);
       frame.getContentPane().add(tabPane);
       frame.show();
}