Mark, thank you very much for your help, which got me on the right track.
Indeed, the problem is that iPad photos, even when they are taken with a
portrait orientation, always carry Exif data that claim a landcape orientation.
Web browsers and many mail clients orient pictures according to
malgosia askanas wrote:
When scrubbing an image attachment such as a jpeg, Mailman seems to always
orient it into landscape mode - irrespective of the orientation of the
original. Is there some way to prevent this?
Whatever is doing what you observe, it's not Mailman. It may be the web