Is there any plugins that can create resized images?

Hi guys,

I read some great advice about creating copies of each image relative to the size of the place holder where it will go. Makes it quicker as the original is loaded then resized. Currently my 6 front page blog header images are chewing up 20kb each in excess which is about 40% of my total page size.

I can do this through Photoshop Save for Web option, but was wondering if there are any plugins that you can specify specific dimensions and it will create multiple versions of the image?

Thanks heaps!