Client Hints
ch
Warning: Starting with version 67, Chrome no longer supports sending Client Hints to third-party origins to prevent them from accessing information that might be unavailable to them otherwise. This feature may return at a later date.
Note: ch
cannot be set as a Source's default parameter, due to the way it interacts with imgix's caching infrastructure.
The ch
parameter opts in specific images to use Client Hints (opens in a new tab), which provide automatic resource selection using browser headers. imgix currently supports three hints, which override or change their respective imgix parameters:
Width
overrides the imgixw
parameterDPR
overrides the imgixdpr
parameterSave-Data
reduces image quality toq=45
and may change the output format of the image
You can use multiple Client Hints—values should be comma-separated. If the browser does not support Client Hints, the other values present in the URL will be used. For example, the URL below will take advantage of the Width
and DPR
Client Hints if present and fall back to an image that's 400 device-independent pixels wide at 2 DPR if the browser doesn't support them:
https://assets.imgix.net/unsplash/bear.jpg?ch=Width,DPR&w=400&dpr=2
Note: All browsers that support Save-Data
will send the header, regardless of whether or not the Client Hint meta tag is present. However, if you want to use the other Client Hints, you will need to include the following in your site's <meta>
tags to ensure that the headers are sent to the browser:
<meta http-equiv="Accept-CH" content="Width,DPR">
For more information and use cases, please see the following:
No Base64 Variant
This parameter does not accept base64-encoded values. All values must be provided as standard UTF8, url-encoded strings.