In each price sheet you create, you can set an additional shipping charge for individual items.
This shipping charge will be used in conjunction with the flat rate shipping set in the Shipping section of the price sheet, and will be added for each item ordered. This extra charge would be added 20 times if the client orders 20 of the same image.
This method is ideal for photographers who have items shipped to their studio first and then re-ship them out to their clients, or for self-fulfilled items that may incur unusually high shipping costs. Or for those photographers offering large or heavy self-fulfilled items which may be costly to ship.
This setup may not be ideal for regular sized prints or for studios that have their orders sent directly to the client.
To set up shipping on a per-item basis, go to Commerce > Pricing and click on the specific price sheet. Then, click the "+" icon under the Shipping column beside a specific item.