I have a site with a lot of thumbnail images that display a larger version using a jQuery lightbox effect when clicked. This works well but it doesn't make good use of the available screen real estate.

To support 1024x768 users I use a minimum image size of 640x640 (so that 640x480 images in either orientation always fit on the screen). However this wastes a lot of space where I could be displaying a higher resolution version to users with a higher screen resolution or larger browser window. For example, for 2560x1600 users I would like to use a 1600x1200 image.

Is there a lightbox plugin that can handle multiple image sizes automatically?

This is a Wordpress site so a Wordpress plugin could also work.

Any suggestions appreciated.