/**
  * 
  * get thumb url
  */
 public function getUrlThumb($thumbSize = "")
 {
     $thumbSize = trim($thumbSize);
     if (empty($thumbSize)) {
         return $this->urlThumb;
     }
     //get thumb url by image url
     if (empty($this->imageID)) {
         if ($thumbSize == "full") {
             return $this->urlImage;
         }
         if (method_exists("UniteProviderFunctionsUG", "getThumbWidth") == false) {
             return $this->urlThumb;
         }
         $thumbWidth = UniteProviderFunctionsUG::getThumbWidth($thumbSize);
         $operations = new UGOperations();
         try {
             $urlThumb = $operations->createThumbs($this->urlImage, $thumbWidth);
             $urlThumb = HelperUG::URLtoFull($urlThumb);
         } catch (Exception $error) {
             if (!empty($this->urlThumb)) {
                 return $this->urlThumb;
             }
             throw new Error($error);
         }
         return $urlThumb;
     } else {
         //with image id
         if (method_exists("UniteProviderFunctionsUG", "getThumbUrlFromImageID")) {
             $urlThumb = UniteProviderFunctionsUG::getThumbUrlFromImageID($this->imageID, $thumbSize);
             if (!empty($urlThumb)) {
                 $urlThumb = HelperUG::URLtoFull($urlThumb);
                 return $urlThumb;
             }
         }
     }
     return $this->urlThumb;
 }