Add More Images Im using FrameMarket GridMarket theme

Add More Images

Im using FrameMarket GridMarket theme and Market Press plugin. I would like to add more images than just one. see : http://frenib.com/store/products/test-product-fifteen

I have one image set as featured image. How do I add more images? I do not want to add them into the product description are like here: http://frenib.com/store/products/test-product-fourteen/

On a separate note: is there a way to attach images on this forum? I dont see a way to attach images when i ask questions on here. there are times when a picture is worth a thousand words and can illustrate a point much faster than trying to explain it.