Life is not simple anymore. New technologies taking us down paths not considered or considered but ignored.
I thought I should update this with the latest position: Basically the issue with the introduction of EXIF rotation flag we have got to a position where to do what the flag indicates is not always the right thing to do. A lot of systems did and still do not handle EXIF which means that users manually rotate images. When investigating a huge library of some 50,000+ photos it was found that the manual rotation in some cases nulls out the EXIF flag and some times not. Also the image EXIF Width and Length tags are sometimes adjusted to reflect the new dimensions after rotation mirroring the Dimensions attribute and in other times they are not.
Basically it appears that there is no obvious algorithm one can apply to get the orientation right in all cases. I stumbled on this which explains the mess we are in now following the introduction of EXIF orientation ! http://keyj.emphy.de/exif-orientation-rant/ - Some of changes introduced in PMS 0.9.8.2 to fix issues I raised have now been regressed. I have help Plex development in raising a support ticket with the development team of the FreeImage Library Plex Media Server uses for auto EXIF rotation but I do not expect any fix from them. Of lots of different applications I tried all but Google Picasa 3.9.0 got some of the manually rotated images display with the wrong orientation. Obviously Google must have put some clever probably patented technology to work out the orientation - very clever.
To cut the story short - I have now asked the Plex Development team to introduce an option on Library Section basis to implement or ignore EXIF Rotation. So watch this space.
