adding custom theme support

I have added custom theme support for backgrounds using

$args = array(
	'default-color' => ' ',
	'default-image' => get_template_directory_uri() . '/images/jn_paper_green_03_03.png',
);
add_theme_support( 'custom-background', $args );

If you look at the home page for this site https://jeannaymark.com – I am trying to figure out if I can add the same type of support for each of the individual specialty boxes.

Does anyone know the correct way or where to find this in the codex?

Thanks