function validate()
 {
     if ($this->hasFile() || $this->current_filename == '') {
         return parent::validate();
     }
     return true;
 }
 function validate()
 {
     if (!parent::validate()) {
         return false;
     }
     if (!is_null($this->_validator) && $this->_validator->getOption('required') && !@getimagesize($this->_value['tmp_name'])) {
         $this->_validator->setErrorCode('mime_types');
         return false;
     }
     return true;
 }