When uploading photos, the orientation of the portrait images is always wrong, even though my photo management software displays them correctly on the screen. Shotwell, F-Spot, Eye of Gnome (system's default picture viewer) all display the photo with the correct orientation. The reason is that the photo orientation is stored in the EXIF data. Any half decent photo viewer correctly interprets EXIF data these days, except for galleria. Note that other Drupal image modules also suffer from the same problem, but it's a problem nonetheless.

A workaround is to manually convert all the images (using lossless rotation, like exifautotran) before uploading them, but it would be so much better if it would just work in galleria.