Through Lazy Load pictures will not be loaded until they are in the viewport of the browser. This reduces both loading times and traffic use.
When Lazy Load is activated the address in the src-attributes of all <img>-tags will be removed and replaced with a small, transparent GIF.
Before the modification for Lazy Load
<img src="my-picture.png" alt="My Picture">
After the modification for Lazy Load
<img data-src="my-picture.png" src="data:image/gif;base64,R0lGODdhAQABAIAAANk7awAAACH5BAEAAAEALAAAAAABAAEAAAICTAEAOw==" alt="My Picture">
This uses the Intersection Observer API, which is supported by modern browsers. If the API is not supported by the browser the picture will be loaded immediately.