NextGen gallery + ecommerce module

Hello.

Sorry but my english is very bad.

I have a problem with the plugin NextGen Gallery and the module ecommerce in pro version.

I try to sell some photographs in my web but when I export the photos with a resolution to can print it, the size of the file is too big.
If I create a gallery whit this pictures, the gallery show the pictures with the full resolution. In this case, the gallery keep open and not show pictures and the options to buy pictures is not shonw.

I want show a picture whit more less resolution in the gallery but when a user buy a photo, the link to download go to a full resolution picture.

This is possible?
Thanks in advance.