code: public String saveScreenshot(String filename, long timeout) {
      return saveScreenshot(filename, timeout, true, new ArrayList<String>());
    }
docs: Take a screenshot of the area this element covers. Saves a copy of the image to the given
  filename.
  
  @param filename the location to save the screenshot
  @param timeout  the number of milliseconds to wait before taking the screenshot
  @return the MD5 hash of the screenshot