G2 + any ecommerce solution?

Hi all,
is there someone that succesfully set up G2 to sell photos?

I would like to sell my photos using G2 but it seems that there is no way to allow the download of high res photos only to people that paid using paypal.

I'm trying to use the zencart integration module but I can't understand how zencart handles shipping (it should allow the paying user to download the ordered files).

It's very hard without a little tutorial.

Any help is really appreciated.

TIA

tony