code: public function init()
      {
          parent::init();
  
          if ($this->notImage === null) {
              $this->notImage = Yii::t('yii', 'The file "{file}" is not an image.');
          }
          if ($this->underWidth === null) {
              $this->underWidth = Yii::t('yii', 'The image "{file}" is too small. The width cannot be smaller than {limit, number} {limit, plural, one{pixel} other{pixels}}.');
          }
          if ($this->underHeight === null) {
              $this->underHeight = Yii::t('yii', 'The image "{file}" is too small. The height cannot be smaller than {limit, number} {limit, plural, one{pixel} other{pixels}}.');
          }
          if ($this->overWidth === null) {
              $this->overWidth = Yii::t('yii', 'The image "{file}" is too large. The width cannot be larger than {limit, number} {limit, plural, one{pixel} other{pixels}}.');
          }
          if ($this->overHeight === null) {
              $this->overHeight = Yii::t('yii', 'The image "{file}" is too large. The height cannot be larger than {limit, number} {limit, plural, one{pixel} other{pixels}}.');
          }
      }
docs: {@inheritdoc}