Comment 4 for bug 482443

I'm also seeing jpegexiforient seemingly doing nothing on files saved from Gimp; I'm not 100% convinced it will actually add the setting to a file that doesn't already have it, but only changes it if it's already in there.

Note that you can add these with the 'exif' tool as well, and it will actually add an EXIF block and the orientation setting if not already there:

$ exif -c --output=portrait-rotated.jpg --ifd=0 --tag=0x0112 --set-value=8 --no-fixup portrait-raw.jpg

After doing that, jpegexiforient seems to actually take effect on the resulting file.