public function setImageOptions($ext = null, $size = null)
 {
     $this->getValidator()->setAllowedExtensions($ext ? $ext : ImageUploadField::config()->default_allowed_extensions);
     $sizeInBytes = $size ? $size : ImageUploadField::config()->default_max_file_size * 1024 * 1024;
     $this->getValidator()->setAllowedMaxFileSize($sizeInBytes);
     return $this;
 }