Custom_Image_Header example

    public function update( $value ) {
        global $custom_image_header;

        // If _custom_header_background_just_in_time() fails to initialize $custom_image_header when not is_admin().         if ( empty( $custom_image_header ) ) {
            require_once ABSPATH . 'wp-admin/includes/class-custom-image-header.php';
            $args                   = get_theme_support( 'custom-header' );
            $admin_head_callback    = isset( $args[0]['admin-head-callback'] ) ? $args[0]['admin-head-callback'] : null;
            $admin_preview_callback = isset( $args[0]['admin-preview-callback'] ) ? $args[0]['admin-preview-callback'] : null;
            $custom_image_header    = new Custom_Image_Header( $admin_head_callback, $admin_preview_callback );
        }

        /* * If the value doesn't exist (removed or random), * use the header_image value. */
        if ( ! $value ) {
            $value = $this->manager->get_setting( 'header_image' )->post_value();
        }

        if ( is_array( $value ) && isset( $value['choice'] ) ) {
            

if ( current_theme_supports( 'custom-header' ) ) {
        // In case any constants were defined after an add_custom_image_header() call, re-run.         add_theme_support( 'custom-header', array( '__jit' => true ) );

        $args = get_theme_support( 'custom-header' );
        if ( $args[0]['wp-head-callback'] ) {
            add_action( 'wp_head', $args[0]['wp-head-callback'] );
        }

        if ( is_admin() ) {
            require_once ABSPATH . 'wp-admin/includes/class-custom-image-header.php';
            $custom_image_header = new Custom_Image_Header( $args[0]['admin-head-callback'], $args[0]['admin-preview-callback'] );
        }
    }

    if ( current_theme_supports( 'custom-background' ) ) {
        // In case any constants were defined after an add_custom_background() call, re-run.         add_theme_support( 'custom-background', array( '__jit' => true ) );

        $args = get_theme_support( 'custom-background' );
        add_action( 'wp_head', $args[0]['wp-head-callback'] );

        if ( is_admin() ) {