code: public function getUrl()
      {
          // returns original url if IO and force lossy are disabled
          if ($this->isFastlyImageOptimizationEnabled() == false && $this->isForceLossyEnabled() == false) {
              return parent::getUrl();
          }
          // retrieves force lossy url or param if force lossy is enabled
          if ($this->isForceLossyEnabled() != false) {
              $this->getForceLossyUrl();
          }
          // retrieves Fastly url if force lossy url is not set
          if (!$this->lossyUrl) {
              $this->getFastlyUrl();
          }
          // returns url with set parameters
          if ($this->lossyParam) {
              return $this->fastlyUrl . $this->lossyParam;
          } elseif ($this->lossyUrl) {
              return $this->lossyUrl;
          } else {
              return $this->fastlyUrl;
          }
      }
docs: Wrapper for original getUrl()
  
  @return string