Depending on what phone your using and what angle the photo is taken at, sometimes it still messes up. Sometimes I have to rotate images on my phone manually to view them properly after taking them.
As a result of this it would be really useful to have a basic rotate function that can be applied to images when creating or editing posts.
Rotate function in XMG:
Current Attached Files view under a post:
Mock up of amended version with a single 90 degree rotate button:
Only a single button would be needed and could be pressed multiple times to achieve the correct orientation.