A simple image viewer in Java

ImageViewer.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ImageViewer implements KeyListener{
    private JFrame frame;
    private ImageIcon image;
    private ImageIcon origImage;
    private JLabel imageLabel;
    private String[] files;
    private int index;

    public static void main(String[] args){
        ImageViewer imgVwr = new ImageViewer(args);
        imgVwr.frame.setVisible(true);
    }

    public ImageViewer(String[] args){
        files = args;
        index = 0;
        frame = new JFrame("Animated GIF");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.addKeyListener(this);
        loadImage();
    }

    private void loadImage(){
        if (imageLabel != null){
            frame.getContentPane().remove(imageLabel);
        }

        if (origImage != null){
            origImage.getImage().flush();
        }

        origImage = new ImageIcon(files[index]);
        while(origImage.getImageLoadStatus() == MediaTracker.LOADING){
            try{
                Thread.sleep(0);
            }
            catch(InterruptedException e){}
        }

        if(origImage.getImageLoadStatus() == MediaTracker.ERRORED){
            imageLabel = new JLabel("Image load encountered an error");
            image = null;
            origImage = null;
        }
        else{
            ImageIcon oldImage = image;
            image = new ImageIcon(origImage.getImage());
            if (oldImage != null){
                oldImage.getImage().flush();
            }
            imageLabel = new JLabel(origImage);
            frame.setTitle(files[index]);
        }
        frame.getContentPane().add(imageLabel);
        frame.pack();
    }

    private void scale(int w, int h){
        if(origImage != null){
            try{
                Image oldImage = image.getImage();
                Image img = origImage.getImage()
                    .getScaledInstance(w, h, Image.SCALE_DEFAULT);
                image.setImage(img);
                oldImage.flush();

                if (imageLabel != null){
                    frame.getContentPane().remove(imageLabel);
                }
                imageLabel = new JLabel(image);
                frame.getContentPane().add(imageLabel);
                frame.pack();
            }
            catch(IllegalArgumentException e){}
        }
    }
         
    public void keyPressed(KeyEvent e){
        switch(e.getKeyCode()){
            case KeyEvent.VK_ESCAPE:
            case KeyEvent.VK_Q:
                // quit
                frame.dispatchEvent(
                        new WindowEvent(frame, WindowEvent.WINDOW_CLOSING));
                break;
            case KeyEvent.VK_SPACE:
                next();
                break;
            case KeyEvent.VK_B:
                prev();
                break;
            case KeyEvent.VK_ENTER:
            case KeyEvent.VK_S:
                showName();
                break;
            case KeyEvent.VK_F:
                zoomIn();
                break;
            case KeyEvent.VK_V:
                zoomOut();
                break;
            default: break;
        }
    }
    public void keyReleased(KeyEvent e){}
    public void keyTyped(KeyEvent e){}

    private void next(){
        index += 1;
        index %= files.length;
        loadImage();
    }
    private void prev(){
        index -= 1;
        while(index < 0){
            index += files.length;
        }
        loadImage();
    }
    private void showName(){
        System.out.println(files[index]);
    }
    private void zoomIn(){
        if(image != null){
            int width = (int)(image.getIconWidth() * 1.1);
            int height = (int)(image.getIconHeight() * 1.1);
            scale(width, height);
        }
    }
    private void zoomOut(){
        if(image != null){
            int width = (int)(image.getIconWidth() * 0.9);
            int height = (int)(image.getIconHeight() * 0.9);
            scale(width, height);
        }
    }

}