Default Background Colors

How are the default background colors chosen? Can I designate which background color is the default for any particular product? Can I edit the size, orientation, color, etc on any given image on any product of that image and have my choices stick (be the default) that a potential customer sees first? When I click on 'Customize Product' to edit all of these options, it seems random whether the changes I've made are what is shown after I submit and exit and then click on that product to see what would be shown to a potential customer. Am I doing something wrong? This is very frustrating.