WordPress.org

Author: Mdkart

This plugin for Wordpress automatically add the rel="lightbox[ID-OF-THE-POST]" to images linked in a post ID-OF-THE-POST is unique per post so all images per post are grouped in one lightbox set.

Doesn't add the the files required for Lightbox (it's only add the rel lightbox tag)! You have to insert yourself in your theme the required files or use a plugin like Lightbox 2 Wordpress Plugin or Lightbox 2.3 plugin for Wordpress