See all the discussion here: https://bugzilla.wikimedia.org/6672
Brion Vibber brion@pobox.com writes:
(And yes, we know that allowing you to preview & fix the rotation *during* the upload process will be a big help. There should be a bugzilla entry ready for comments somewhere.)
I couldn't find one, so I opened one:
https://bugzilla.wikimedia.org/32875 - Provide a chance to undo rotation
Mark.