Image Rotation / EXIF Orientation (my trials)

smallIT

Joined: 2012-10-28
Posts: 7
Posted: Mon, 2012-10-29 06:00

There doesn't seem to be an open topic for the EXIF orientation/image rotation inconvenience. This topic and this topic both mention the issue; there is an allusion, but no definitive response, to what is happening. I did some testing, maybe my results below will be useful. In short, it is the interplay of ImageMagick, Gallery, and web browsers, and their interpretations of EXIF orientation of JPEG.

For an uploaded image with EXIF Orientation of 180 degrees, as confirmed by Gallery Photo Detail showing Orientation 3:Upside-down :
- Mac Safari 5.1.7 and Firefox 15.0.1 ignore EXIF orientation and display image upside -down
+ iOS Safari and iCab honour EXIF rotation info and display image correctly
+ Mobile theme version of website will display thumbnail rightside-up,
- but the full image is upside-down (in both iOS Safari or iCab)
* Use of the Jpegtran module to rotate photo does not modify the image file itself. The image presentation is therefor opposite for all results above.

The interesting blog post "EXIF orientation handling is a ghetto" compares online photo services and their presentation of images with EXIF Orientation. No real solutions, but it makes me wonder if perhaps there is something that can be done with the Gallery database. A stopgap solution is for images to be manipulated pre-upload using an editor (preferably lossless), except that mobile users may be out of luck. Mobile uploads are the future, and the future is now. ;-)

All in all, the disorientated image files uploaded by mobile users for desktop viewers, and those for iOS mobile viewers after a Jpegtran modification causes a bit of a ruckus, I think. There may be a away to fix it within Gallery itself, but I am not sure how that would happen.




* Gallery Version: 3.0.4 (Ricochet) * Gallery Wind Theme *