Do not store the current screenshot if not needed

[phmLabs]

Use the executor instead.

 public function takeScreenshot($save_as = null) {
 $screenshot = base64_decode(
 $this->executor->execute('takeScreenshot')
 );
 if ($save_as) {
 file_put_contents($save_as, $screenshot);
 }
 return $screenshot;
 }

[phmLabs]

 $codeCWebdriver = $this->getModule("WebDriver");
 // @var $codeCWebdriver RemoteWebDriver

 $executor = $codeCWebdriver->webDriver->getCommandExecutor();
 /* @var \WebDriverCommandExecutor $executor */