Art Galleria allows you to track multiple editions, for example if you have 100 prints. There are two different ways to do this:

This method works best for prints where you have a large quantity of identical items.

The easiest and quickest way is to create one record per edition, and set a quantity (e.g., 100). Every time you generate an invoice, it will draw the quantity sold from the available quantity.  

This works best for small editions where each item is unique in some way.

Another way you can track multiple items is by creating one record—with images and all the artwork information—and then duplicate that item. The Inventory ID will automatically increase, and indicate it is part of a series. For example, INV-0123 will become INV-0123/1, INV-0123/2, INV-0123/3, etc. 

With this method, you can sell each item on the invoice individually, and even add additional info to each piece (for instance, they may have different attributes).