[css-color] Feedback on the image-orientation CSS property

Hi,

In this discussion thread, concerns were raised regarding whether
image-orientation should be a CSS property:
http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2014-April/254148.html

tl;dr:

   - Property should be move to markup: it is more semantic than stylistic.
   Image orientation affects the content.
   - It would be desirable to take image orientation into account when
   drawing an image to 2D canvas or WebGL. If orientation is expressed by a
   CSS property, that would imply making canvas draws dependent on style
   computation.

Thoughts?