Java source code examples for handling image files

In addition to my Java image FAQ and list of Java libraries to read and write image files this page shows small working Java programs that demonstrate how to deal with image files with the standard runtime library and the most popular external libraries.

The programs

Loading and displaying an image with Toolkit (Viewer.java) - java.awt.Toolkit is used to load an image, MediaTracker makes sure that the image is loaded completely and finally the image is inserted into a Frame and displayed. So this 40-line-program is basically a minimum image viewer.
Load an image, scale it to thumbnail size and save it as JPEG (Thumbnail.java) - java.awt.Toolkit is used to load an image, BufferedImage.drawImage does the scaling and the package com.sun.image.codec.jpeg saves the thumbnail image as a JPEG file (Java 1.2 or higher required, Sun JDK / JRE recommended).
Capture a screenshot and save it as PNG file, using ImageIO (Screenshot.java) - requires Java 1.4 or higher.
Colorize a rectangular part of an image and add text to the bottom (Highlight.java) - requires Java 1.4 or higher.