How do I remove the instant Full Size Large image of each product from their product page?

I setup a store on my existing website on ephisecureemail.com/store, using your marketpress plugin. When I loaded products into the store I notice that on their product page, the featured image of the product is full blown over the product information. How do I take that off so that it only shows the normal size image of the product?

Also, i added the shopping cart widget to the sidebar of the store. However, if you add items to your cart, you will see that the shopping cart expands out side of the sidebar boundary and bleeds over into the body of the store page rather than remain only in the side bar. How do I fix that?