The fetchpriority="high" attribute tells the browser to fetch one specific image ahead of everything else competing for bandwidth. Applied to the Largest Contentful Paint image — usually your hero or the first big image above the fold — it’s one of the highest-return single changes you can make: Google’s own test cut LCP from 2.6 seconds to 1.9 seconds with nothing but that attribute. WordPress 6.3 and later can add it automatically, but it doesn’t always pick the right image, so it’s worth checking.
What It Actually Does
When a page loads, the browser discovers a lot of resources at once — scripts, stylesheets, fonts, images — and has to decide what order to fetch them in. By default images are “low” or “auto” priority, which means your hero image can end up queued behind things that don’t affect what the visitor sees first. fetchpriority="high" moves that one image to the front of the line. Because LCP measures when the largest visible element finishes rendering, getting its image sooner directly improves the score.
The Rules
- Use it on exactly one image per page — the LCP element. If you mark several images high priority, you’ve just recreated the original problem.
- Never lazy-load the LCP image.
fetchpriority="high"andloading="lazy"on the same image work against each other. The LCP image should load eagerly. - Leave every other image at default. Don’t set
fetchpriority="low"on everything else — “auto” is already correct for them.
How to Apply It on WordPress
- Find your LCP element. Open the page in Chrome DevTools, run a Performance trace, and look at what the LCP marker points to. It’s usually the hero image or the first in-content image.
- Check whether WordPress already handled it. View source and search for
fetchpriority="high". Since WordPress 6.3, core tries to add it to the first suitably large image. If it’s on the right image, you’re done. - If it’s on the wrong image or missing: the reliable fix is to make sure your hero image is a real, early
<img>in the markup (not a CSS background, not lazy-loaded), large enough for core’s heuristic to pick it. Block themes let you set a featured/cover image that core can identify. - Re-test. Run the trace again and confirm LCP dropped and the attribute is on the element the LCP marker points to.
| Image | fetchpriority | loading |
|---|---|---|
| LCP image (hero / first large image) | high | eager (never lazy) |
| Everything below the fold | auto (leave default) | lazy |
It’s Not a Substitute for the Rest
fetchpriority gets the LCP image fetched sooner; it doesn’t make the image smaller or the server faster. Pair it with a properly sized image in WebP or AVIF, a reasonable server response time, and no render-blocking CSS or JS above the fold. We covered the full image side in WordPress Image Optimization Guide for 2026 Sites and the broader Core Web Vitals picture in Core Web Vitals for WordPress in 2026.
Frequently Asked Questions
Does WordPress add fetchpriority automatically?
Since WordPress 6.3, core adds fetchpriority="high" to the first image it judges large enough to be the LCP element. The heuristic is good but not perfect — check that it landed on the right image.
Can I put fetchpriority=”high” on more than one image?
You can, but you shouldn’t. Marking several images as high priority splits bandwidth between them and defeats the purpose. Use it on the single LCP image only.
What if my hero is a CSS background image?
CSS background images can’t take the fetchpriority attribute and are discovered later by the browser. If your LCP element is a background image, the better fix is usually to make it a real <img> element, or to preload it in the page head.
Featured image: original illustration.