The plugin only makes use of CSS and font-icons to build the layouts so it will be retina ready.
The images uploaded by the user are from the user responsibility.
A Retina Ready image needs to be 2x the normal size. So if you have an image that you want it to be 100px x 100px, you would need to upload a 200px x 200px image. We recomend the use of the free plugin WP Retina 2X Plugin created by Jordy Meow to ensure your website is ready to display retina ready images.