WP_Customize_Header_Image_Setting

19final class WP_Customize_Header_Image_Setting extends WP_Customize_Setting {20 21	/**22	 * Unique string identifier for the setting.23	 *24	 * @since 3.4.025	 * @var string26	 */27	public $id = 'header_image_data';28 29	/**30	 * @since 3.4.031	 *32	 * @global Custom_Image_Header $custom_image_header33	 *34	 * @param mixed $value The value to update.35	 */36	public function update( $value ) {37		global $custom_image_header;38 39		// If _custom_header_background_just_in_time() fails to initialize $custom_image_header when not is_admin().40		if ( empty( $custom_image_header ) ) {41			require_once ABSPATH . 'wp-admin/includes/class-custom-image-header.php';42			$args                   = get_theme_support( 'custom-header' );43			$admin_head_callback    = isset( $args[0]['admin-head-callback'] ) ? $args[0]['admin-head-callback'] : null;44			$admin_preview_callback = isset( $args[0]['admin-preview-callback'] ) ? $args[0]['admin-preview-callback'] : null;45			$custom_image_header    = new Custom_Image_Header( $admin_head_callback, $admin_preview_callback );46		}47 48		/*49		 * If the value doesn't exist (removed or random),50		 * use the header_image value.51		 */52		if ( ! $value ) {53			$value = $this->manager->get_setting( 'header_image' )->post_value();54		}55 56		if ( is_array( $value ) && isset( $value['choice'] ) ) {57			$custom_image_header->set_header_image( $value['choice'] );58		} else {59			$custom_image_header->set_header_image( $value );60		}61	}62}