/**
  * Get post meta
  *
  * @param string   $key     Meta key. Required.
  * @param int|null $post_id Post ID. null for current post. Optional
  * @param array    $args    Array of arguments. Optional.
  *
  * @return mixed
  */
 static function meta($key, $args = array(), $post_id = null)
 {
     $post_id = empty($post_id) ? get_the_ID() : $post_id;
     $args = wp_parse_args($args, array('type' => 'text', 'multiple' => false));
     // Always set 'multiple' true for following field types
     if (in_array($args['type'], array('checkbox_list', 'file', 'file_advanced', 'image', 'image_advanced', 'plupload_image', 'thickbox_image'))) {
         $args['multiple'] = true;
     }
     $meta = get_post_meta($post_id, $key, !$args['multiple']);
     // Get uploaded files info
     if (in_array($args['type'], array('file', 'file_advanced'))) {
         if (is_array($meta) && !empty($meta)) {
             $files = array();
             foreach ($meta as $id) {
                 // Get only info of existing attachments
                 if (get_attached_file($id)) {
                     $files[$id] = RWMB_File_Field::file_info($id);
                 }
             }
             $meta = $files;
         }
     } elseif (in_array($args['type'], array('image', 'plupload_image', 'thickbox_image', 'image_advanced'))) {
         if (is_array($meta) && !empty($meta)) {
             $images = array();
             foreach ($meta as $id) {
                 // Get only info of existing attachments
                 if (get_attached_file($id)) {
                     $images[$id] = RWMB_Image_Field::file_info($id, $args);
                 }
             }
             $meta = $images;
         }
     } elseif ('taxonomy_advanced' == $args['type']) {
         if (!empty($args['taxonomy'])) {
             $term_ids = array_map('intval', array_filter(explode(',', $meta . ',')));
             // Allow to pass more arguments to "get_terms"
             $func_args = wp_parse_args(array('include' => $term_ids, 'hide_empty' => false), $args);
             unset($func_args['type'], $func_args['taxonomy'], $func_args['multiple']);
             $meta = get_terms($args['taxonomy'], $func_args);
         } else {
             $meta = array();
         }
     } elseif ('taxonomy' == $args['type']) {
         $meta = empty($args['taxonomy']) ? array() : get_the_terms($post_id, $args['taxonomy']);
     } elseif ('map' == $args['type']) {
         $field = array('id' => $key, 'multiple' => false, 'clone' => false);
         $meta = RWMB_Map_Field::the_value($field, $args, $post_id);
     } elseif ('oembed' == $args['type']) {
         $field = array('id' => $key, 'clone' => isset($args['clone']) ? $args['clone'] : false, 'multiple' => isset($args['multiple']) ? $args['multiple'] : false);
         $meta = RWMB_OEmbed_Field::the_value($field, $args, $post_id);
     }
     return apply_filters('rwmb_meta', $meta, $key, $args, $post_id);
 }

 /**
  * Format a single value for the helper functions.
  * @param array $field Field parameter
  * @param array $value The value
  * @return string
  */
 public static function format_single_value($field, $value)
 {
     return RWMB_Image_Field::format_single_value($field, $value);
 }

 /**
  * Get uploaded file information.
  *
  * @param int   $file_id Attachment image ID (post ID). Required.
  * @param array $args    Array of arguments (for size).
  * @return array|bool False if file not found. Array of image info on success
  */
 static function file_info($file_id, $args = array())
 {
     return RWMB_Image_Field::file_info($file_id, $args);
 }

 /**
  * Enqueue scripts and styles
  *
  * @return void
  */
 static function admin_enqueue_scripts()
 {
     parent::admin_enqueue_scripts();
     add_thickbox();
     wp_enqueue_script('media-upload');
     wp_enqueue_script('rwmb-thickbox-image', RWMB_JS_URL . 'thickbox-image.js', array('jquery'), RWMB_VER, true);
 }

 /**
  * Add actions
  *
  * @return void
  */
 static function add_actions()
 {
     // Do same actions as file field
     parent::add_actions();
     // Attach images via Ajax
     add_action('wp_ajax_rwmb_attach_media', array(__CLASS__, 'wp_ajax_attach_media'));
 }

 /**
  * Enqueue scripts and styles
  *
  * @return void
  */
 static function admin_enqueue_scripts()
 {
     // Enqueue same scripts and styles as for file field
     parent::admin_enqueue_scripts();
     wp_enqueue_style('rwmb-plupload-image', RWMB_CSS_URL . 'plupload-image.css', array('wp-admin'), RWMB_VER);
     wp_enqueue_script('rwmb-plupload-image', RWMB_JS_URL . 'plupload-image.js', array('jquery-ui-sortable', 'wp-ajax-response', 'plupload-all'), RWMB_VER, true);
     wp_localize_script('rwmb-plupload-image', 'RWMB', array('url' => RWMB_URL));
     wp_localize_script('rwmb-plupload-image', 'rwmb_plupload_defaults', array('runtimes' => 'html5,silverlight,flash,html4', 'file_data_name' => 'async-upload', 'multiple_queues' => true, 'max_file_size' => wp_max_upload_size() . 'b', 'url' => admin_url('admin-ajax.php'), 'flash_swf_url' => includes_url('js/plupload/plupload.flash.swf'), 'silverlight_xap_url' => includes_url('js/plupload/plupload.silverlight.xap'), 'filters' => array(array('title' => _x('Allowed Image Files', 'image upload', 'rwmb'), 'extensions' => 'jpg,jpeg,gif,png')), 'multipart' => true, 'urlstream_upload' => true));
 }

 /**
  * Get field HTML
  *
  * @param mixed $meta
  * @param array $field
  *
  * @return string
  */
 public static function html($meta, $field)
 {
     $i18n_title = apply_filters('rwmb_thickbox_image_upload_string', _x('Upload Images', 'image upload', 'meta-box'), $field);
     // Uploaded images
     $html = parent::get_uploaded_files($meta, $field);
     // Show form upload
     $html .= "<a href='#' class='button rwmb-thickbox-upload' data-field_id='{$field['id']}'>{$i18n_title}</a>";
     return $html;
 }

 /**
  * Enqueue scripts and styles
  *
  * @return void
  */
 static function admin_print_styles()
 {
     global $post;
     // Enqueue same scripts and styles as for file field
     parent::admin_print_styles();
     wp_enqueue_script('plupload-all');
     wp_enqueue_style('rwmb-plupload-image', RWMB_CSS_URL . 'plupload-image.css', array(), RWMB_VER);
     wp_enqueue_script('rwmb-plupload-image', RWMB_JS_URL . 'plupload-image.js', array('jquery-ui-sortable', 'wp-ajax-response', 'plupload-all'), RWMB_VER, true);
     //Heartcode Canvas Loader
     wp_enqueue_script('heartcode-canvasloader', 'http://heartcode-canvasloader.googlecode.com/files/heartcode-canvasloader-min-0.9.1.js');
     wp_localize_script('rwmb-plupload-image', 'rwmb_plupload_defaults', array('runtimes' => 'html5,silverlight,flash,html4', 'file_data_name' => 'async-upload', 'multiple_queues' => true, 'max_file_size' => wp_max_upload_size() . 'b', 'url' => admin_url('admin-ajax.php'), 'flash_swf_url' => includes_url('js/plupload/plupload.flash.swf'), 'silverlight_xap_url' => includes_url('js/plupload/plupload.silverlight.xap'), 'filters' => array(array('title' => _x('Allowed Image Files', 'image upload', RWMB_TEXTDOMAIN), 'extensions' => 'jpg,gif,png')), 'multipart' => true, 'urlstream_upload' => true, 'multipart_params' => array('_ajax_nonce' => wp_create_nonce('plupload_image'), 'action' => 'plupload_image_upload', 'post_id' => $post->ID)));
     //Links to loading and error images to allow preloading
     wp_localize_script('rwmb-plupload-image', 'rwmb_plupload_status_icons', array('error' => RWMB_URL . "img/image-error.gif", 'loading' => RWMB_URL . "img/loading.gif"));
 }

 /**
  * Normalize parameters for field
  *
  * @param array $field
  *
  * @return array
  */
 static function normalize_field($field)
 {
     $field['js_options'] = array('runtimes' => 'html5,silverlight,flash,html4', 'file_data_name' => 'async-upload', 'browse_button' => $field['id'] . '-browse-button', 'drop_element' => $field['id'] . '-dragdrop', 'multiple_queues' => true, 'max_file_size' => wp_max_upload_size() . 'b', 'url' => admin_url('admin-ajax.php'), 'flash_swf_url' => includes_url('js/plupload/plupload.flash.swf'), 'silverlight_xap_url' => includes_url('js/plupload/plupload.silverlight.xap'), 'multipart' => true, 'urlstream_upload' => true, 'filters' => array(array('title' => _x('Allowed Image Files', 'image upload', 'meta-box'), 'extensions' => 'jpg,jpeg,gif,png')), 'multipart_params' => array('field_id' => $field['id'], 'action' => 'rwmb_plupload_image_upload'));
     $field = parent::normalize_field($field);
     return $field;
 }

 /**
  * Normalize parameters for field
  *
  * @param array $field
  *
  * @return array
  */
 static function normalize_field($field)
 {
     $field = parent::normalize_field($field);
     $field['multiple'] = false;
     return $field;
 }