WordPress responsive LCP images (srcset, picture) and the Core Web Vitals
srcset, <picture>, or a single fixed image URL: how many sites ship responsive hero candidates and how responsive markup changes Largest Contentful Paint (73% with <picture> and 75% with srcset vs 69% without).
Four in five WordPress sites, 79.1%, have no responsive LCP image markup. Of the 20.9% that do, 87% use srcset, and 75% of those sites have a good LCP, against 70% of all WordPress sites.
LCP pass rate
Sites with srcset responsive LCP image markup have a good LCP most often: 75%, against 70% of all WordPress sites. Sites with <picture> responsive markup have it least often, at 73%.
Responsive LCP image markup usage
One in five WordPress sites uses responsive LCP image markup, and 87% of those use srcset.
How srcset and <picture> affect the four LCP phases
Across the four LCP sub-parts in Chrome's field data, the largest gap between srcset and no sits in resource load delay: 225 ms median for srcset against 365 ms for no. Overall median field LCP is 1.8s for srcset (TTFB 1099 ms, load delay 225 ms, load duration 163 ms, render delay 251 ms) versus 2.0s for no.
Responsive LCP image markup per framework
On jQuery, 80% of sites use no responsive LCP image markup, and 69% of jQuery sites have a good LCP, against 70% of all sites. On Vue, 82% of sites use no, and 68% of Vue sites have a good LCP.
Alpine 349 sitesNo responsive markup 70%srcset attribute 16%<picture> element 14%80%
jQuery 57,286 sitesNo responsive markup 80%srcset attribute 18%69%
Vue 4,721 sitesNo responsive markup 82%srcset attribute 15%68%
React 2,117 sitesNo responsive markup 76%srcset attribute 21%61%Responsive LCP markup or the framework
Does the framework explain the responsive LCP image markup difference?
On jQuery, 73% of sites with srcset responsive LCP image markup have a good LCP, against 68% of jQuery sites with no. Within jQuery, sites with srcset have a good LCP more often. On Vue, 72% of sites with srcset responsive LCP image markup have a good LCP, against 67% of Vue sites with no. Within Vue, sites with srcset have a good LCP more often.
Why srcset and <picture> matter most on mobile viewports
Without srcset or <picture>, a mobile phone on a cellular connection downloads the same 1600px or 2000px hero banner prepared for a desktop monitor. Providing width descriptors in srcset with a matching sizes attribute lets Chrome's preload scanner pick the candidate that fits the device's screen width and pixel ratio before layout runs.
Understanding responsive LCP image markup
Render hero banners through wp_get_attachment_image() with an accurate sizes attribute instead of hardcoding a raw file URL or a CSS background-image. WordPress core has generated srcset automatically since version 4.4, yet 79.1% of WordPress LCP elements have no responsive markup because CSS background images and custom page-builder blocks bypass core image helpers. WordPress sites using <picture> (73% good LCP) or srcset (75% good LCP) beat fixed hero images (69% good LCP).
By Arjen Karel · 63,295 crawled WordPress sites (60,855 with all devices Chrome field data, 60,125 sites with responsive LCP image markup, October 2026). How we measured.