Albums created with Jalbum are stand-alone HTML pages. They work very well without needing a CMS.
If , for whatever reason, you want to integrate your album into a site created by a CMS, you just need to provide an iframe within a Joomla page. You can see how to do this in this Jalbum tutorial.
If you are unable to apply this tutorial to your Joomla page, then the folk at Joomla should be able to help you (Joomla is, after all, a Content Management System).
If this still does not help, give some thought to using a skin that already incorporates a shopping cart (Aeneid, Chameleon, FotoPlayer).
Alternatively, you could register and configure a free shopping cart account at .
It is fairly easy to insert "Add to Cart" (or "Buy Now") and "Show/Submit cart" links to almost any skin that doesn't already have a built-in shopping cart option.
The shopping cart processing will all take place on your pages at Mal's E-commerce SSL secure server.