https://bugzilla.wikimedia.org/show_bug.cgi?id=66337

            Bug ID: 66337
           Summary: Scaling of images should take place in a linear colour
                    space
           Product: MediaWiki
           Version: unspecified
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: Unprioritized
         Component: File management
          Assignee: wikibugs-l@lists.wikimedia.org
          Reporter: bawolff...@gmail.com
                CC: aarcos.w...@gmail.com, bawolff...@gmail.com,
                    bryan.tongm...@gmail.com, dispen...@toolserver.org,
                    fflo...@wikimedia.org, gti...@wikimedia.org,
                    mtrac...@member.fsf.org
       Web browser: ---
   Mobile Platform: ---

Dispenser mentioned to me that our image scaling is working on non-linear sRGB
colour space, which causes some less than ideal results on dark images

Background on issue:
* http://www.4p8.com/eric.brasseur/gamma.html [Specifically mentions Wikipedia
as doing it wrong]
* http://www.imagemagick.org/Usage/resize/#resize_colorspace

For image magick, it looks like this can be addressed by just adding some
command line flags (which flags unfortunately vary by version). [Except
possibly not jpeg as that's shrunk by libjpeg]

Its unclear if something similar can be done in vips well still using the very
efficient sequential read and not creating a giant temporary file. There is a
-a option to vipsthumbnail that could maybe be used.

(If it can only be on image magick and then not for jpeg, we possibly wouldn't
want to do it at all to keep things consistent. Requires more investigation
anyhow)

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