Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Content-DPR response header is used to confirm the image device to pixel ratio in requests where the screen
DPR client hint was used to select an image resource.
|Header type||Response header, Client hint|
|Forbidden header name||no|
|CORS-safelisted response header||no|
DPR client hint is used to select an image the server must specify
Content-DPR in the response. If the value in
Content-DPR is different from the
DPR value in the request (i.e. image DPR is not the same as screen DPR) then the client must use the
Content-DPR for determining intrinsic image size and scaling the image.
Content-DPR header appears more than once in a message the last occurrence is used.
Content-DPRwas removed from the client hints specification in draft-ietf-httpbis-client-hints-07. The Responsive Image Client Hints spec proposes to replace this header by specifying intrinsic resolution/dimensions in EXIF metadata.
The image device pixel ratio, calculated according to the following formula: Content-DPR = Selected image resource size / (Width / DPR)
DPR header example.
BCD tables only load in the browser
- Improving user privacy and developer experience with User-Agent Client Hints (web.dev)
- Device client hints
- HTTP Caching > Varying responses and