
Image EXIF Orientation Bug – or Feature? - praveenscience
https://blog.praveen.science/crazy-image-exif-orientation-bug-or-feature/
======
anonymfus
>I’ve found the results strange in Safari and Chrome, since there’s this CSS
property for <img />, image-orientation, and with it one can say to use the
EXIF declared on the photo metadata to fix the orientation. The default value
is 0deg. If you want show the image with the correct orientation, the value
must be from-image.

I went to the linked specification ([https://www.w3.org/TR/css3-images/#image-
orientation](https://www.w3.org/TR/css3-images/#image-orientation)) and "from-
image" is not specified here as a possible value of "image-orientation".

~~~
garaetjjte
It seems that Firefox from-image is nonstandard (from-image in specification
is only defined for image-resolution). And default behavior of ignoring EXIF
rotation seems correct according to this weird specification:

>Note that some devices will "tag" an image with some metadata indicating its
correct orientation, so image viewing software can do the necessary
transformation themselves. Due to legacy compatibility restraints, Web
browsers are required to ignore this data by default. A future level of this
specification is expected to have a value that applies the metadata-specified
transformation automatically.

IMO EXIF rotation should be applied always, and any CSS rotations should
combine with it, not override.

~~~
leni536
> IMO EXIF rotation should be applied always, and any CSS rotations should
> combine with it, not override.

I agree. EXIF rotation is a part of the image and it's just an implementation
detail of the image data. Browsers shouldn't leak this.

~~~
michaelt
Presumably the issue is "Given that browsers that ignore EXIF rotation already
exist, should modern browsers display the same page differently?"

~~~
anonymfus
Yes because it will fix more pages than it will break.

~~~
praveenscience
But what about the compatibility, graceful degradation, etc. of the browsers
that yet don't support this feature? Won't that break everything else?

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leni536
The exiftran utility can strip the EXIF orientation tag and apply the rotation
_losslessly_ to the image. Looks like it worth doing it. AFAIK imagemagick
reencodes the image.

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dade_
Correct conclusion, strip the info. EXIF is a mess on the web, thankfully
Digikam easily normalizes all of my photos with simple batch process. Not my
videos though.

~~~
praveenscience
Most of the online upload services do it. Like Imgur strips these information.
:)

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Theodores
One thing I one day want to try is to include some unique search terms in an
image EXIF description to see if Googlebot picks it up in a way that is
subsequently searchable.

As for Wordpress people using third party services to remove bloat from images
in a paid for, tediously manual way - don't! Configure your server to do it
with Google's mod_pagespeed. You can serve src_set images whilst you are at it
that way making the web quicker and more eco friendly.

~~~
mnw21cam
Or just load the image into GIMP and make use of its nifty image optimisation
while saving it again.

(Oh, and feature. Definitely feature.)

------
cbr
To fix these:

    
    
        convert -auto-orient in.jpg out.jpg

~~~
maaark
A note for clueless windows users:

    
    
        convert /?
        Converts a FAT volume to NTFS.
        
        CONVERT volume /FS:NTFS [/V] [/CvtArea:filename] [/NoSecurity] [/X]
        
        
          volume      Specifies the drive letter (followed by a colon),
                      mount point, or volume name.
          /FS:NTFS    Specifies that the volume will be converted to NTFS.
          /V          Specifies that Convert will be run in verbose mode.
          /CvtArea:filename
                      Specifies a contiguous file in the root directory
                      that will be the place holder for NTFS system files.
          /NoSecurity Specifies that the security settings on the converted
                      files and directories allow access by all users.
          /X          Forces the volume to dismount first if necessary.
                      All open handles to the volume will not be valid.
    
    

You probably can't do any damage attempting to use it to convert images, but
there might be a way to screw up attempting to convert an image so badly you
destroy your filesystem.

~~~
cbr
It's unfortunate that ImageMagick decided to call their primary command
"convert".

