The State of Web Vitals

Image dimensions set

Whether images declare width/height or aspect-ratio - the classic CLS guard.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Phone field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for Image dimensions set

Whether images declare width/height or aspect-ratio - the classic CLS guard.

3
Categories
In the distribution
54.2%
Fleet share
Top: has_none
79.3%
Sites with any
Of has_none

54.2% of images declare no dimensions at all.

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
2

The image dimensions set mix who uses what, and how stable each group is

Median CLS (sites using feature)
0
0.10
0.20
0.30
0.40
0.50
Has none0.0054% of sites
Has dimensions0.0044% of sites
Has aspect ratio0.002% of sites
VariantShare of sitesMedian
Has none
54%
0.00
Has dimensions
44%
0.00
Has aspect ratio
2%
0.00

Image dimensions set. On the fleet: 54.2% has none, 44.3% has dimensions, 1.5% has aspect ratio. 79.3% of sites use at least one has_none.

Lowest-share bucket: CLS 0.00. Highest-share bucket: CLS 0.00. r = +0.45.

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

Passing CLS per bucket every category and count level at once - color is the pass rate

1
2
3
4
5
6
7
8
9
10
11
12
Has none 54.2%
91
90
90
90
90
89
88
87
86
86
83
85
Has dimensions 44.3%
87
88
89
89
91
91
90
90
89
89
89
89
Has aspect ratio 1.5%
89
82
87
85
83
85
73
76
91
71
82
← few of this category on the pagemany →
60%95%+ of sites passing CLS Faded cells: under 100 sites

Each row is a category, each column its own count bucket (few on the left, many on the right); the cell is the share of those sites passing CLS.

Has none swings the hardest: 91% of sites pass CLS with few, 85% with many. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
4

Few vs many - does quantity cost CLS? the pass rate with few vs many of each category

60%70%80%90%100% few → many
Has none 54.2% 91% → 85%
Has dimensions 44.3% 87% → 89%
Has aspect ratio 1.5% 89% → 91%
% of sites passing CLS · hollow ring = pages with few, solid dot = pages with many

Per category: the pass rate among pages with FEW of it (hollow ring) against pages with MANY (solid dot), worst trend first. Thin buckets are excluded from the endpoints.

More Has none costs the most: the CLS pass rate falls from 91% with few to 85% with many. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
5

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

Width and height on an img are not about sizing the image. They are about reserving its space. The browser knows the aspect ratio before the file arrives, lays out a right-sized box, and the image lands without moving anything. Without them the image arrives, the box inflates, and the content below jumps.

This is the cheapest CLS fix that exists. Modern CSS keeps the image responsive anyway (height auto), so the old reason for dropping the attributes is gone.

How does this affect the Core Web Vitals?

Of the 3 categories, Has aspect ratio separates passing sites from failing sites the most. Where Has aspect ratio is rare: 89% pass the CLS. Where it is common: 82%.

Go fix it Fix layout shift from auto-sizing images → CLS from images and media →
Related signals Fonts per page → DOM size → Bytes by resource type → Images per page → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured