Computes the aspect ratio of an image using the HTML width and height attributes so that it can be used for sizing an image using CSS before it loads.


To correctly compute the final dimensions of an image (before it is fully loaded), this feature computes the aspect ratio from the HTML width and height attributes, so that it can be used to compute the final size when e.g. "width: 100%; height: auto;" is used in CSS. This avoids unnecessary relayouts when the image loads (compared to <img src="foo.jpg" style="width: 100%">



Editor's draft

Status in Chromium


Enabled by default (tracking bug) in:

  • Chrome for desktop release 79
  • Chrome for Android release 79
  • Android WebView release 79

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Shipped/Shipping
  • No signal
  • No signal
  • No signals


Intent to Prototype url

Intent to Prototype thread

Search tags

img, aspect-ratio,

Last updated on 2020-12-21