coderef

<img sizes="auto" loading="lazy">Limited availability

The sizes="auto" attribute for the &#x3C;img> HTML element sets the layout size for the image based on the computed layout size when choosing a source from the srcset. This attribute only applies to images with the loading="lazy" attribute.

Not yet supported in all major browsers — check the table and provide a fallback.

How to use ↓Compare browsers

Browser support

DesktopChrome
1–125Not supported
126+Supportedsince Jun 11, 2024
Current: 155
Edge
12–125Not supported
126+Supportedsince Jun 13, 2024
Current: 154
Firefox
1–149Not supported
150+Supportedsince Apr 21, 2026
Current: 157
Safari
✕Not supportedup to 27
Current: 27
MobileChrome Android
18–125Not supported
126+Supportedsince Jun 11, 2024
Current: 155
Firefox Android
4–149Not supported
150+Supportedsince Apr 21, 2026
Current: 157
Safari iOS
✕Not supportedup to 27
Current: 27

How to use

Not supported in Safari, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.

Example

Full syntax and examples are on MDN: sizes.

Feature detection

JS · check before using
if ("sizes" in document.createElement("img")) {
  // the sizes attribute/property of <img> is supported
}

Documentation (MDN)

Specification