I have tried that and it still opens the image full screen, but now in a lightbox.
What I would like, if possible, is to retain the functionality of the previous gallery. Click this link and you will see what was happening;
You will see that the images all display as square. When you click one of the thumbnails the image displays in the main image window and does not open up full screen. Is it possible for me to retain this functionality? I also notice that all images are displayed as thumbnails below the main image, but now the first image is not displayed as a thumbnail.