Rocket Lazy Load is a simple but powerful plugin with a tiny (less than 2kb) lazy load script without any jQuery and others libraries. What all this script does is, it displays images on pages only when they are visible to your user’s eyes i.e. only when show up on screen with down scroll. Hence, this trick reduces the number of HTTP requests mechanism and improves your website’s loading time.
Load an image of your WordPress site only when it is visible in the to the user, this way you can improve your site’s loading time and save server’s bandwidth too.