/**
  * read image contents from cached
  * @param $urlArray
  * @return mixed
  */
 public static function fetchImagesCache($urlArray)
 {
     !static::$mc && (static::$mc = new mc());
     $fileNameArray = array_map(function ($url) {
         return basename($url);
     }, $urlArray);
     return static::$mc->batchGet($fileNameArray);
 }