This plugin adds a simple Javascript to your WordPress website that will check for each image if there is a retina version available. This will make sure that your images (logo’s, buttons, images with text) look sharp on Apple devices with retina displays.
When you have for example a logo of 200 by 200 pixels called “Logo.png”, you will need to upload a second image of 400 by 400 pixels called “Logo@2x.png” in the exact same directory.