I learned way more about java today than I wanted to, but it was for a good cause.
I had a mess of images scanned by our Geology Department and imported into Dspace. Filter-media produced some ugly thumbnails for these (and only these) images:
Thumb — http://www.uvm.edu/~waw/archives/00000041.jpg.jpg
Meanwhile, all these Geology JPEGs had high-res TIFF files associated with them, too. I wanted TIFF thumbnails. So I started hacking away at JPEGFilter.java And I discovered "Java Advanced Imaging" — I downloaded "JavaTM Advanced Imaging 1.1.2 CLASSPATH install" and "Java Advanced Imaging Image I/O Tools 1.0"
Installed the jars and .so files in dspace-1.2.1beta4-source/lib Added some "import" statements and 3 lines of new code to JPEGFilter.java , and like magic, two birds killed with one stone