Image loading strategies on Wix sites

Sites with CSS background image loading strategies have a good LCP most often: 94%, against 94% of all Wix sites. Sites with lazy below-the-fold image loading have it least often, at 93%.

Eager above-the-fold is the most used: 99.2% of Wix sites. CSS background is 90.6% of Wix sites.

Across the four LCP sub-parts in Chrome's field data, the largest gap between CSS background and lazy below-the-fold sits in resource load delay: 446 ms median for CSS background against 479 ms for lazy below-the-fold. Overall median field LCP is 1.1s for CSS background (TTFB 406 ms, load delay 446 ms, load duration 109 ms, render delay 149 ms) versus 1.2s for lazy below-the-fold.

React sets the image loading strategies to CSS background on 91% of its sites, and 94% of React sites have a good LCP, against 94% of all sites.

FrameworkImage loading strategies on its sitesGood LCP

Wix sites with image loading strategies 5,619 sitesEager above-the-fold <img> 99%CSS background images 91%Eager below-the-fold <img> 74%Lazy below-the-fold (loading="lazy") 62%Lazy above-the-fold (loading="lazy") 42%94%

React 5,618 sitesEager above-the-fold <img> 99%CSS background images 91%Eager below-the-fold <img> 74%Lazy below-the-fold (loading="lazy") 62%Lazy above-the-fold (loading="lazy") 42%94%

Eager above-the-fold <img> CSS background images Eager below-the-fold <img> Lazy below-the-fold (loading="lazy") Lazy above-the-fold (loading="lazy")

Does the framework explain the image loading strategies difference?

Almost every site with CSS background image loading strategies is a React site, and almost every React site has CSS background image loading strategies, so the data can't tell CSS background image loading strategies and React apart.

How browser viewport intersection gates lazy image fetches

Standard <img> elements without loading="lazy" are queued by the HTML preload scanner before layout runs (446 ms median LCP load delay on sites with eager above-the-fold images). When loading="lazy" is present on an image inside the initial viewport (42.1% of sites), Chromium withholds the network request until style and layout confirm viewport intersection, pushing median LCP resource load delay to 449 ms.