Lazy loading is an image loading technique that allows customers to view onscreen content on your site more quickly.
Without lazy loading all the images on a page will load right away. This delays the time until other content is displayed on the screen.
By using lazy loading, visible images on screen will be loaded before offscreen images.
Images that are offscreen will be loaded later on.
By implementing lazy loading you can provide your customers with a faster experience on your site. You can speak to your theme developer about implementing this.