Bugzilla

The problematic 90 degree rotation here is actually a **supplemental CSS-transform rotation that slack is adding**, with the mistaken expectation that the image will be shown at the wrong orientation and needs an additional transform.

We should probably do some webcompat outreach to Slack folks and see if they can address this on their end by removing the explicit CSS transform & instead explicitly styling the user-uploaded images with `image-orientation:from-image` (to make this work the same way regardless of the default value).

Also: it turns out the in-chat image is a server-side-munged file, which has probably had the EXIF data stripped out of it (I'm guessing) and has probably been rescaled/reoriented so as not to have any need for EXIF rotation.  So that's why that version of the image works reliably both before and after the change in default behavior.

The problematic 90 degree rotation here is actually a **supplemental CSS-transform rotation that slack is adding**, with slack mistakenly expectating that the image will be shown at the wrong orientation (due to the old `image-orientation:none` default) and hence assuming that it needs an additional transform to display properly.

We should probably do some webcompat outreach to Slack folks and see if they can address this on their end by removing the explicit CSS transform & instead explicitly styling the user-uploaded images with `image-orientation:from-image` (to make this work the same way regardless of the default value).

Also: it turns out the in-chat image is a server-side-munged file, which has probably had the EXIF data stripped out of it (I'm guessing) and has probably been rescaled/reoriented so as not to have any need for EXIF rotation.  So that's why that version of the image works reliably both before and after the change in default behavior.

The problematic 90 degree rotation here is actually a **supplemental CSS-transform rotation that slack is adding**, with slack mistakenly expectating that the image will be shown at the wrong orientation (due to the old `image-orientation:none` default) and hence assuming that it needs an additional transform to display properly.

We should probably do some webcompat outreach to Slack folks and see if they can address this on their end by **removing the (dynamically added) explicit CSS transform** & instead explicitly styling the user-uploaded images with `image-orientation:from-image` (to make this work the same way regardless of the default value).

Also: it turns out the in-chat image is a server-side-munged file, which has probably had the EXIF data stripped out of it (I'm guessing) and has probably been rescaled/reoriented so as not to have any need for EXIF rotation.  So that's why that version of the image works reliably both before and after the change in default behavior.

The problematic 90 degree rotation here is actually a **supplemental CSS-transform rotation that slack is adding**, with slack mistakenly expectating that the image will be shown at the wrong orientation (due to the old `image-orientation:none` default) and hence assuming that it needs an additional transform to display properly.

We should probably do some webcompat outreach to Slack folks and see if they can address this on their end by **removing the (dynamically added) explicit CSS transform & instead explicitly styling the user-uploaded images with `image-orientation:from-image`** (to make this work the same way regardless of the default value).

Also: it turns out the in-chat image is a server-side-munged file, which has probably had the EXIF data stripped out of it (I'm guessing) and has probably been rescaled/reoriented so as not to have any need for EXIF rotation.  So that's why that version of the image works reliably both before and after the change in default behavior.