Java 5 supports reading GIF files. Java 6 also supports writing GIF files. I needed a nice way to write gif images from Java 5. A lot of GIF packages exists for Java 5. But most of them does not give the same nice result as the implementation by Sun. Since I couldn’t upgrade to Java 6 in my project, I backported parts of the javax.imageio package from openjdk-6-src-b09-11_apr_2008 (Can be downloaded from http://openjdk.java.net), so that it can run on Java 5. I’ve introduced new package names, so that this package will not mess with the standard javax.imageio package. Feel free to use it. But remember that it comes with no guarantees! If you find any problems you can mail me at java6-gif-backport/at/jakobielsen_dot_net.
Read more at http://www.jakobnielsen.net/java6-gif-backport