[Plugin: NextGEN Gallery] Putting Pay Pal Add to Cart Button under next gen gallery thumbnails

I have a page where people can see the thumbails of my prints. I have the paypal add cart button and codes I want to show under each thumbnail. That way people can pick the one they want and add to the cart.

How and where do I accomplish doing that?

Here is the current page: http://jeanbmoyer.com/shop-for-prints/

I sure would appreciate any help someone could give me.

Thanks so much.

http://wordpress.org/extend/plugins/nextgen-gallery/