Following up on my meta-data stripping script comes up a script that will resize pictures and optionally create a thumbnail.

Basic commands are -r WIDTHxHEIGHT to set the size to scale to, -t to create 120x120 thumbnails and -q to set the quality setting. The final argument can either be an image file or a folder, it'll recurse through the folder and work on every image at the top level. Thumbnails are stored in a folder named thumbs with the same name as the original file.