JPEG rotate lossless
Some cameras store images in a different orientation than what is intended for display. They will add an EXIF tag to indicate that the image is rotated. It is possible to rotate a JPEG image losslessly; that is, rotate without uncompressing and recompressing the image. This is important to avoid loosing image quality.
There are a few common tools, exiftran, and jhead. I have not done a lot of testing, but it seems like exiftran is the best tool to use.
exiftran -ai *.[jJ][pP][gG]
jhead -autorot *.jpg