To speed up the perceived loading time of pages, images that are out of site - or "below the scroll" can be deferred in their loading until they are within view (or nearly so).

As you scroll down this page, images should be loading just before their point of view. Appropriate images are also loaded when the browser is resized.

If a DOM node is passed to the function, all images within that node will be lazy-loaded. If an array is passed, all DOM nodes that are elements within the array will be lazy-loaded. If no value is passed - all images are lazy-loaded.

If you do not have Javascript enabled, the images are displayed as normal.