[Plugin: WP e-Commerce] Nextgen Galleries and add to cart

I wish to use nextgen gallery already set-up to sell Photographers. I have got the layout how I wish I just need to be able to link nextgen to a e-commerce product to allow me to have a shopping cart and the ability for people to be able to select a size and purchase the product via paypal and for me to then ship out the relevant item.

I have looked at Wp E-commerce and though that with there nextgen plug-in would be able to do this however this does not seem to be the case but rather just a pay now button to paypal.

Does anyone know how I go about allowing people click a button and bring up a list of size and a choice select the size they wish and add to cart. I’m not sure how you would link the image to a product in Wp-E commerce

I’m Currently not able to just get the current pay-now button to work let alone link it with a cart.

Currently using
Portfolio Press (Theme)
wordpress (Latest version)
Nextgen (Last Version before current one)
Wp E-commerce + nextgen plug-in addon (Current)

https://www.ads-software.com/extend/plugins/wp-e-commerce/