Accept header for images loaded from img elements lacks jpegxr and webp

External Issue #19481764

Details

Author
Karl-Johan S.
Created
Nov 1, 2018
Privacy
This issue is public.
Found in
  • Microsoft Edge
  • Internet Explorer
Found in build #
44.17763
Reports
Reported by 2 people

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Steps to reproduce

When loading an image through an <img>-element both Edge (and IE11) sent “image/png, image/svg+xml, image/jxr, /image/; q=0.8, //; q=0.5” in the accept header of the request. This allowed for sniffing support for JPEG XR which was great but is absent in the latest version of both Edge and IE11.

The new accept header in Edge is shortened to just “image/png, image/svg+xml, image/*; q=0.8, /; q=0.5” even though it still supports jpegxr and webp was just introduced but there is no way to sniff support for any of them.

IE11 just sends "/" in the accept header.

This can be seen https://demo.openlib.se/sv/news/%2Fsaga-3-0 where we earlier returned jpegxr for Edge and IE11 and was now expecting at Edge to get webp. Instead we are back to returning regular jpegs…

Attachments

Comments and activity

  • Microsoft Edge Team

    Changed Assigned To to “Veerabhadra r.”

  • Hi, Thanks for reporting your feedback, We unable to reproduce your issue. Can we get more information like screenshots or related links, that will help us to investigate further and reproduce it. 
    Also check the latest build.
    Build details:
    Microsoft Edge 44.17763.1.0
    Microsoft EdgeHTML 18.17763

    Thanks
    The MS Edge Team

  • Hi,

    It seems like my initial report became a bit faulty due to the markdown rendering. Where it was supposed to say */* the stars were made it bold instead. My mistake.

    Anyway, I created a repro at https://karl-sjogren.com/edge-19481764-repro/ were I simply load an image. I’ve attached a screenshot that shows the inspector window with the Accept-header sent when loading the image along with the settings panel showing my Edge and EdgeHTML versions.

    Edge-accept-headers.png

    It might be a good idea to open it from the attachment list instead of trying to read it here though.

    The expected result here is that the accept header would include both “image/jxr” and “image/webp” but it has neither.

  • Correct, Edge is sending the Accept header from the Fetch standard, rather than augmenting it with WebP as Firefox and Chrome do. 

    For in-page images, the <picture> element should be used and the browser will select the best supported source. For direct top-level navigations to image URLs, unfortunately there’s no good workaround like picture.

  • I can accept that (standards are great after all) even though I think it is regretable that this turned out for the worse for anyone visiting my pages in IE and Edge for now. However, for IE11 we can’t use the picture element (according to https://caniuse.com/#search=picture) so they will be locked out from JPEG XR forever now unless we use browser sniffing…

  • Microsoft Edge Team

    Changed Status to “External”

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