Thank you for all the answers here, I really appreciate it.
I found a different solution that I wanted to share. Jpegtran does lossless transforms of jpeg images. I discovered it when I installed ImageMagick and it is part of the tool set installed.
To use, type:
jpegtran -rot 90 DSC_0276.jpg > DSC_0276-rot.jpg
Then you can trash the original file. I wrote a script to allow me to click a rotate button in the finder and boom. Rotated and the original is sent to the trash (recoverable if there is an error)
You can also use ImageMagic itself. ImageMagic has an "auto-rotate" option that will read the EXIF header and rotate the JPEG image to the same as the camera's gravity sensor. The EXIF header is then modified. That command is:
convert -auto-orient DSC_0276.JPG DSC_ROT.JPG
Or use ImageMagic to rotate:
convert -rotate "90" DSC_ROT.JPG DSC_ROT.JPG
ImageMagic can work on the file in place; ie,
convert [options] INFILE OUTFILE where INFILE and OUTFILE can be the same name. jpegtran needs two separate file names and you need to have a script or other workflow to account for that.
ImageMagic's -auto-orient is definitely lossless and I believe the 90, 180 ,270 degree rotations are lossless. I cannot guarantee that.
jpegtran only does lossless transforms.
You can use MacPorts to install these.