Performance · Website glossary

Lazy loading

Quick answer · What is Lazy loading?

The deferral of nonessential resource loading until the resource is needed or near use.

IN PRACTICE

Lazy loading: an example

Images far below the first screen load as a visitor approaches them.

KEEP IN MIND

Deferring the main visible image can delay important content; use the technique selectively.

Put the idea to work

Frequently asked questions

What is a practical example of Lazy loading?

Images far below the first screen load as a visitor approaches them.

Should the main visible image always be lazy-loaded?

Deferring the main visible image can delay important content; use the technique selectively.

Which concepts should I read alongside Lazy loading?

Largest Contentful Paint: LCP reports when the largest eligible visible content element in the initial viewport is rendered.
Responsive images: Image markup that lets a browser select suitable sources for layout size, resolution, or art direction.