Where can I find more information about Java image manipulation and processing?

Check out Jonathan Knudsen's columns on java.oreilly.com plus the archive of my Media Programming JavaWorld columns at: www.javaworld.com/javaworld/topicalindex/jw-ti-media.html

In particular, Jonathan and I co-wrote a Java 2D image processing article at: www.javaworld.com/javaworld/jw-09-1998/jw-09-media.html

You might also check out Jonathan's book, Java 2D Graphics. There is also book titled "Image processing in Java" by Douglas Lyon, but I have not yet reviewed a copy and so cannot give a direct recommendation. You can read reviews and order a copy online.