This is the link of how-to setup Lightbox2 and IImage Browser plugin for easy photo insertion to a posting. It is very nice!
However, the setup process is not that simple.
Make sure you install PHP-GD rpm package (GD2) for the thumbnail creation by IImage Browser. It is necessary.
http://www.thehotcrew.com/2006/05/16/lightbox-wordpress-plugin/
By the way, I have used the below WP plugin for lightbox2.
http://zeo.unic.net.my/notes/lightbox-js-version-20/