I don't have this one configured with lightbox or anything fancy, but adding extra images to a product is not hard ... just a little obscure.
Here's an example (from a demo store, a sandbox that I'm not going to keep up for very long)
From the WordPress Dashboard home:
Products -> Products -> (select the product you want to add images to)
then "Add Media", which is towards the top of the screen.
here is a pic of the "Add Media" screen, where you can see the three options on the left, for "Insert Media", "Create Gallery", "Set Featured Image" and also for "Insert from URL" (I never use the last one on self-contained sites.)
For this product, I used only images that were already in my media library, one for the "Featured Image" and the whole lot of the color variations for the image gallery.
Also, products that have variations (like different colors), you can assign a different image to each variation and the featured image will update depending on the variation selected.