id свойства 31, свойство множественное

AddEventHandler("iblock", "OnBeforeIBlockElementAdd",	Array("MyClass",	"OnBeforeIBlockElementAddHandler"));
		class MyClass
		{
			// создаем обработчик события "OnAfterIBlockElementAdd"
			function OnBeforeIBlockElementAddHandler(&$arFields)
			{
				
				if($arFields["IBLOCK_ID"] == 14){
					// dbg($arFields,true);
					foreach($arFields[PROPERTY_VALUES][31] as &$file):
					   CAllFile::ResizeImage(
						 $file, 
						 array("width" => "200", "height" => "200"), 
						 BX_RESIZE_IMAGE_PROPORTIONAL);
					endforeach;
				}

			}
		}