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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.