In order to use these buttons on your own website, you'll first want to save them to your computer so that you can upload them to your own website. To save each one just right click on each graphic. You will get a pop-up menu, and one of the choices will be to "Save Image As..." (or similar). Then just save it to your computer. .
These images are the corresponding graphics that will appear in your cart if you select the standard theme in your shopping cart configuration. You do not need to download these.
