Thank you for responding so quickly.  I understand that the Juicebox-Pro configuration settings allow the thumbnails to be turned off, but here's what I'm wondering...

My gallery sometimes has one image and at other times has more than one image, so I would like the thumbnails to be hidden when there is only one image and displayed when there are more than one, without having to change the configuration settings back and forth.  Is this possible with Juicebox-Pro?