Reorder custom header code

// in the header of a post.

add_theme_support('post-thumbnails');

// - add support for custom menus

add_theme_support('menus');

// - add support for header image

add_theme_support('custom-header', array('default-image'=>get_template_directory_uri().'/img/header.jpg', 'uploads'=>true));

// - add support for custom menus

add_theme_support('menus');

function register_my_menu() {

        register_nav_menu('new-menu',__( 'New Menu' ));

}