BigCommerce - Product Main Image Alignment

We have a store hosted on BigCommerce and the main image on the product page needs to be centered. Our product images have different dimensions so where a 600px x 600px image will center just fine, a 243px x 600px will push to the left. I know other stores have done this - frankly it should be built into BigCommerce but thats another story! If you have done this before, this will probably take your 5 minutes to resolve. You MUST have experience with BigCommerce.