When you add an image from the Stack Exchange iOS app, the media library is rendered in portrait orientation, even when the app itself is in landscape.
To duplicate, turn your iPad so it is in landscape orientation. Create a question. Add an image. Select "Photo Library."
As an unrelated aside, I noticed this issue while reporting a different bug. Making people wait for 20 minutes before they can report additional bugs seems a bit counter productive in an app beta test.