so for me, if I'm in the (android) official CoSo app and start a new post, hit the camera icon from that, and either take a new portrait-orientation pic, or select an existing portrait-orientation pic from the 'Files' icon, the pic posts rotated.

But if I launch my camera independent of the CoSo app & take a picture, and *then* go into CoSo & select that pic from 'Files', the orientation is correcvt.