WordPress.org

Author: Leon Bogaert

Finds images in your posts and if the image sizes specified in the tag are smaller then the images on disk, they are resized. Also works for remote linked images. It is so simple, it doesn't even need configuration. If it doesn't behave as excpected: mail me, or edit the source :)

It's best used with some caching plugin, so it doesn't hit the harddisk on with every image. Look at wp-cache2 or supercache