In-Post Attachment Thumbnails w/Lightbox Viewer

[Supersix]

I searched for an answer on this issue but have been unable to find anything...
We're using thumbs in posts for images w/lightbox enabled.
However, when clicking the thumbs the lightbox pop-up is waaaaay to small.
Its not much larger than the thumb. The photos are much larger.
What is the setting in 3.8 to increase the lightbox view to larger viewable image?

Should look like this [post #5] but larger:
http://www.vbulletin.com/forum/showt...box+image+size

Thanks all