Lazy loading is a technique that delays loading images and other media until the visitor actually needs to see them. Instead of loading everything on a page at once when it first opens, lazy loading only fetches content when it is about to come into view as the visitor scrolls down.
Why it improves performance
A page with ten images would normally load all ten the moment someone visits — even if the visitor only reads the top half and never scrolls further. With lazy loading, only the images in the visible part of the screen load immediately. The rest load on demand as the visitor scrolls.
This makes your page feel faster to load, reduces the amount of data transferred on initial visit, and improves your Core Web Vitals scores — particularly the time it takes for the main content to appear.
Is it built into WordPress?
Yes. WordPress has included native lazy loading for images since version 5.5. The browser handles it automatically using the loading="lazy" attribute on images. For most WordPress sites, this works without any additional configuration.
One thing to watch
The main image or hero image at the top of a page should not be lazy loaded — it is already in the visitor’s viewport and should load immediately. Lazy loading it actually delays the most important visual element, which hurts your LCP score. This is a common misconfiguration worth checking.
Read more about image optimisation in WordPress and explore the performance knowledge base.