Fotosizer is a free batch photo/image resizer tool. It lets you resize hundreds of photos in a matter of minutes in a quick and easy way.
This program was perfect for me when I was wanting to customize special C artwork. Most of you kill that option but I got genre icons, made them real small to fit in the top right corner of the screen, its like sick. I shrunk the genre art by using the option "custom size" in the app here.