Hey Zenners

I have Zen Lightbox installed and working but I wonder if a feature I'm trying simply doesn't work?!

I have additional images on some of my products, Lightbox works perfect.

What I have tried to do is put a link to an image on a product information page (ie, a link to a picture of a t-shirt sizing chart) but it won't load in Lightbox. Is this by design or have I got a problem?!

Many thanks in advance.
Natty