title: Capture full-height screenshots from Browserstack with Nightwatch
body: <p>I want to capture full-height screenshots from a Nightwatch test, using Browserstack - I can capture the visible screen, but not the entire document.</p>
  
  <p>I've tried this:</p>
  
  <pre><code>browser.execute(function () {
      // get document dimensions
  }, [], function (result) {
      // browser.resizeWindow(to value sent as result)
      browser.saveScreenshot('filename.png');
  });
  </code></pre>
  
  <p>but while the resulting image has the correct width, the height is limited to (I think) the resolution of the browser opened in Browserstack.</p>
  
  <p>Is it possible to achieve this?</p>