It’s missing this –
//* Add Image upload to WordPress Theme Customizer
add_action( 'customize_register', 'epik_customizer' );
function epik_customizer(){
require_once( get_stylesheet_directory() . '/lib/customize.php' );
}
//* Include Section Image CSS
include_once( get_stylesheet_directory() . '/lib/output.php' );
Add that inside your functions file. I’ll be including this in the next update soon, but the above code should fix it.