The State of Web Vitals

LCP image format

The image format of the LCP resource.

Field data PhoneDesktopAll Scope All sites Q1 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.

12
Categories
58,649 sites
49.6%
Top share
jpg
0.03
Top CLS
Median for jpg

49.6% of LCP images are JPEG. 26.8% are WebP, 6.2% AVIF.

The State of Web Vitals · Q1 2026 · 94,910 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
*0.020% of sites
avif0.026% of sites
jpg0.0350% of sites
webp0.0327% of sites
png0.0315% of sites
svg+xml0.032% of sites
gif0.031% of sites
VariantShare of sitesMedian
* 58 sites
0%
0.02
avif 3,616 sites
6%
0.02
jpg 29,073 sites
50%
0.03
webp 15,689 sites
27%
0.03
png 8,632 sites
15%
0.03
svg+xml 1,250 sites
2%
0.03
gif 323 sites
1%
0.03

Little daylight between the groups: every variant sits near 0.02 median CLS. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
3

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

VariantSitesPassing CLSCLS
Webp 26.8% 15,689 78% 0.03
Avif 6.2% 3,616 78% 0.02
Png 14.7% 8,632 77% 0.03
Jpg 49.6% 29,073 77% 0.03
Svg+xml 2.1% 1,250 77% 0.03
Gif 0.6% 323 75% 0.03
* 0.1% 58 68% 0.02
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

No variant stands out: pass rates sit between 75% and 78%. computed

The State of Web Vitals · Q1 2026 · 94,910 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, 92% 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 94,910 sites, representing millions of real page loads · How we measured