/**
* Method return JSON array containing info about image.
*
* @param gd - GD object used for retrieving info about image
* @param file
*
* @return string JSON array explained in manipulate method comment
*/
private function getImageInfoInJSON(GD $gd,$file) {
return '{"fileName":"' . $file . '","width":' . $gd->getWidth() . ',"height":' . $gd->getHeight() . '}';
}