I like the image previews/thumbnails that appear in the threads from the actual site. I assume you're rendering/screenshotting the site for mobile/desktop in order to generate the previews.

Is there a particular tool you're using/that you'd recommend? Headless Chrome, PhantomJS, NightmareJS? Do you just wait an arbitrary amount of time to assume the necessary visuals have loaded/rendered, or is there a feedback mechanism to indicate when it's ready to be captured?