Okay, I downloaded/installed/activated the jQuery Lightbox plugin. Still not working. I'm getting the same results: I open the page where the gallery is, I inserted the gallery as image list, I click on an image and the image loads in a new page. In Gallery > Options > Effects, I have:
JavaScript Thumbnail effect: Lightbox
Link Code Line: rel="lightbox[%GALLERY_NAME%]"
On the page it shows the gallery properly: [nggallery id=2]
I still have all plugins disabled except NextGen and the new jQuery plugin. The jQuery plugin I have is as described above...
Used to overlay images on the current page. Original jQuery Lightbox by Balupton. Version 0.22 | By Pedro Lamas | Visit plugin site
Bummer....