When lots of images are getting loaded, it will slow down the client browser; too many image requests will even slow down the web server. One common approach is to split the pages and distribute images and content equally. Another approach is to exploit JavaScript's power and avoid unnecessary image requests at the client level. The latter technique is called lazy-loading . In lazy-loading, the image requests are blocked until the image gets under the browser viewport, that is, until the user has physical view of the image.