A: This depends on what buttons you are talking about. The buttons available to be changed can be found at: Shopping Cart > Store Appearance > Scroll down to Images

There are two ways to add your own buttons.

Without Catalog Manager: Go to the images section in Store Appearance. If all of your buttons are located in one place just type in the base path URL to it (eg:http://www.yourdomain.com/images/).

Now you need only to type in the image filenames in the below fields. If you don't use the Base Path type in the exact URL to it.

If you have Catalog Manager: If you have already uploaded images to the Image Manager (Catalog Manager > Images). Just click "Browse" and insert the image.