Image Manipulation in Java

I've been writing some quick tests for image manipulation in Java. I found this page very useful with some nice and clear simple examples.

I'll put my code on here if I don't use it in my coursework but I've basically got a test application that either pulls an image from file using ImageIO.read or grabs a screenshot (based on this example). I've then got functions that allow me to alter the colour of the image, to flip the image or to graffiti it with a selection of coloured shapes. Once the image has been manipulated, it's written to a new file.

I'm quite pleased with my test app (the graffiti is pretty) so here's hoping I can work out how to use it in the courswork.