The State of Web Vitals

LCP image format

The image format of the LCP resource.

Field data PhoneDesktopAll Scope All sites Q2 2026 edition · Desktop field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for LCP image format

The image format of the LCP resource.

15
Categories
111,716 sites
49.6%
Top share
jpg
0.03
Top CLS
Median for jpg

49.6% of LCP images are JPEG. 26.6% are WebP, 6.1% AVIF.

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv
2

LCP image format who uses what, and how stable each group is

Median CLS
0
0.05
0.10
0.15
0.20
0.25
*0.010% of sites
avif0.026% of sites
gif0.021% of sites
jpg0.0350% of sites
webp0.0327% of sites
png0.0315% of sites
svg+xml0.032% of sites
VariantShare of sitesMedian
* 104 sites
0%
0.01
avif 6,818 sites
6%
0.02
gif 651 sites
1%
0.02
jpg 55,415 sites
50%
0.03
webp 29,710 sites
27%
0.03
png 16,502 sites
15%
0.03
svg+xml 2,498 sites
2%
0.03

Little daylight between the groups: every variant sits near 0.01 median CLS. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv
3

Passing CLS per LCP image format which group passes the CLS most often

VariantSitesPassing CLSCLS
Avif 6.1% 6,818 79% 0.02
Webp 26.6% 29,710 78% 0.03
Gif 0.6% 651 78% 0.02
Svg+xml 2.2% 2,498 77% 0.03
Jpg 49.6% 55,415 77% 0.03
Png 14.8% 16,502 76% 0.03
* 0.1% 104 69% 0.01
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site

79% of Avif sites pass CLS. * trails 10 points behind, leaving 31% of its sites failing. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv
4

Why this matters for the Core Web Vitals, and where to start fixing it

The format sets the bytes per pixel, and the LCP's load time scales with the bytes. The same hero photo is far smaller as AVIF or WebP than as JPEG, and PNG for photos is the classic mistake: a lossless format doing a lossy job. SVG is its own case, tiny and sharp at any size for logos and illustrations.

Nobody should convert images by hand. An image CDN or a build step serves the best format each browser supports from one source file. The format mix is mostly a measure of which sites have that step.

How does this affect the Core Web Vitals?

LCP image format correlates with the LCP. With GIF, 90% of sites pass the LCP. With Svg+xml, 83% do.

Go fix it Optimize images for Core Web Vitals → JPEG XL and Core Web Vitals → Optimize the LCP image →
Related signals LCP priority hint → LCP origin → LCP responsive markup → LCP discovery → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured