Digicam JPEG Exif header manipulation tool

jhead is used to display and manipulate data contained in the Exif
header of JPEG images from digital cameras. jhead can also be used
to manipulate some aspects of the image relating to JPEG and Exif
headers, such as changing the internal timestamps, removing the
thumbnail, or transferring Exif headers back into edited images after
graphical editors deleted the Exif header.

Homepage: http://freshmeat.net/redir/jhead/4822/url_homepage/jhead