How to correct sideways picture when posting. Attempted several options, need advise? Thanks!

I have fiddled with this a bit. My theory-

Because the iPhone can take pics that auto rotate, they have no bottom, no anchor. They'll settle how they like when posting on forum. You can fix this by editing the pic.

First load pic and enter edit. Notice the horizon, pic is already at an angle. No anchor.



Then select the rotate tool. The little square thingy.



Then drag the bottom of the pic to rotate it slightly. Notice the horizon after rotation.



Get it right and hit 'done'. Post a correctly anchored pic.