The browser discovers fonts and CSS background images late, after parsing CSS. preload fetches them up front so they're ready when needed — directly improving LCP and reducing font swap flashes.
How to fix it
- Preload your primary web font (and add
font-display: swap). - Preload the LCP image if it's set via CSS rather than an
<img>. - Preload sparingly — only truly critical, above-the-fold assets.
<link rel="preload" as="font" type="font/woff2" href="..." crossorigin>