I know that this has come up often, but the ability to rotate photos (and/or video) within an application is such a basic feature that it is not comprehensible why Plex doesn’t have it.
I have uploaded a large number of pictures, all of which were oriented correctly on my Windows 10 machine, only to have a large number of them misoriented - even upside down - on Plex.
This is yet another call to add this obvious feature to Plex. I currently have a Plex Pass, and this would be a great feature to add for those on the fence between using the free version and paying.