I get a little warning message concerning the possible degradation of the file when rotating. I'm sure many of you have seen it.

Also, why the hell won't my D80 save the files rotating the correct way? When I take a photo vertically, it is displayed correctly on the camera's LCD, but the file transfer switches it around so that I have to rotate it on the computer? VERY frustrating and time consuming! I just spent an hour just rotating the damn things!

it's boiling down to your image manipulation software.

there is a lossless jpeg transformation that can be done to rotate pics, but the built in software probably doesn't have it. i use acdsee pro.

additionally, when batch rotating images the software can look at exif data to determine the camera orientation when the shutter was snapped, and align it accordingly.

without LOSSLESS jpeg rotation you have to decode and recompress the jpeg, which will result in image degredation.

hth
ken