Hi there,

As you can see from this example in our demo, you can add description:

(view large version)

And this is how it looks in the backend:

(view large version)

I hope we're talking about the same lightbox portfolio type.

Hi there,

I've added the description in the caption area, where it really should be and where it works:

(view large version)

So what you need to do is edit the Featured Image and set the description there.

Sorry for complicating it, I wasn't sure where the description was.