This plugin provides the option to select a default custom background.
By default, Genesis doesn't turn on WordPress Custom Backgrounds. Genesis Custom Backgrounds enables custom backgrounds and creates an option to enable selection of a default background from the sets of backgrounds provided by StudioPress. Currently, it is broken down to Dark and Light backgrounds with subfolders. You can easily provide the user more options by simply uploading more backgrounds with in either the light or dark folders. Upload using the following structure, folder: camo & files: camo-1.png, camo-2.png, and camo-3.png (in all lowercase). Furthermore, you can also upload a custom background via the WordPress Custom Background via Appearance > Background. You can easily add customization ability for the site to easily switch default backgrounds or upload their own (which will always overwrite the default).