http://www.sentex.net/~mwandel/jhead/usage.html

Jhead ist ein textbasiertes Hilfsprogramm zur Entnahme der Einstellungendigitaler Kameras aus 
dem von vielen Digitalkameras verwendetenDateiformat EXIF. Es behandelt die verwirrend vielen 
verschiedenen Möglichkeiten und zeigt diese als Blendenwert, Verschlusszeit, usw. an.Das 
Programm kann auch die Größe der JPEG-Dateien von digitalen Kamerasohne Informationsverlust 
reduzieren, indem es die von den Digitalkamerasim EXIF-Header gespeicherten Miniaturbilder löscht.



-    Bilder automatisch anhand der EXIF-Daten drehen
( https://www.commander1024.de/wordpress/2010/06/bilder-automatisch-anhand-der-exif-daten-drehen/ )

Rotation tag manipulation

-autorot 
Using the 'Orientation' tag of the Exif header, rotate the 
image so that it is upright. The program 'jpegtran' is used to perform the rotation. This 
program is present in most Linux distributions. For windows, you need to get a copy of it. 
After rotation, the orientation tag of the Exif header is set to '1' (normal orientation). 
The Exif thumbnail is also rotated. Other fields of the Exif header, including dimensions are 
untouched, but the JPEG height/width are adjusted.This feature is especially useful with newer 
digital cameras, which set the orientation field in the Exif header automatically using a built 
in orientation sensor in the camera.

-norot 
Clears the Exif header rotation tag without altering the image. You may find that your images 
have rotation tags in them from your camera, but you already rotated them with some lossless 
tool without clearing the rotation tag. Now your friendly browser rotates the images on you 
again because the image rotation tag still indicates the image should be rotated. Use this 
option to fix this problem. You may also want to regenerate the thumbnail using the -rgt option.