Wallmander&Co created an awesome new WordPress plugin that allow you to instantly check your website and all its pages in different screen resolutions like 320×480, 768×1024, 1024×768. You can instantly perform responsive test of your WordPress site and see how your website looks like in small screen devices like smartphones and tablets etc.
Mobile Previewer is a cool WordPress plugin. After activation it automatically adds a small light frame (visible only to logged in users) at the bottom right corner in the frontend of your website.
All you need to do is hover over its screen resolution sizes and it will automatically generate and show you mobile preview of current page.