WordPress has a number of default Customizer panels that are in core and applied to all themes – these include Menu and Widgets as well as Site Identity and Static Front Page.     Once you add_theme_supports in your themes function.php…

Here is a guide to add a single background image to a widget using the Customizer in WordPress, I have written up on this topic before utilising some Genesis code used in the Altitude Pro theme to be able to use on other  Genesis…