Multiple product image problem

I am setting up my first e commerce wordpress website (currently in localserver), using Mayashop theme and Jigoshop plugin. I have setup multiple images for a product.
Now when you click on Image thumbnail below featured image in my website. It appears in a popup in the same size as of thumbnail.
while in this website which is using same theme as mine. “http://chaifashions.com/shop/charmed-collection/trisha-summer-dress-2/” if you click on an image thumbnail below featured image. The image in thumbnail appears in place of the featured image.
How can i do that?