Hmm... it appears the application is not properly handling EXIF > Image > Orientation values correctly (see http://sylvana.net/jpegcrop/exif_orientation.html for an explanation of these values). Currently, portrait-orientation photos stored in landscape mode, but with EXIF orientation tags to compensate, are displayed upside-down within Cornice's preview window.
They are also shown on their side in the thumbnail mode, which is an inconvenience, but not a show-stopper. :/
[Deleted duplicate report in comments of news story - mod JTH]
It's a known issue. We need a Python developer to pick it up.
Sometimes, the impossible can become possible, if you're awesome!