exiftool works fine with files generated from Nikon, but always errors out for any Gimp-generated files from these Nikon files (such as after post-processing and saving as jpg). Google Photos is able to read and handle the meta data correctly.
Ubuntu 13.10
Gimp 2.8.6
exiftool: 9.13
photos: Nikon D3100 JPG
exiftool -GPSLongitudeRef=W -GPSLatitudeRef=N -GPSLongitude=122.306909 -GPSLatitude=37.864130 jetty-pano-*.JPG
Warning: Truncated PreviewIFD directory. IFD dropped. - jetty-pano-DSC_0136-1.JPG
Error: [minor] Bad PreviewIFD directory - jetty-pano-DSC_0136-1.JPG
Warning: Truncated PreviewIFD directory. IFD dropped. - jetty-pano-DSC_0137-1.JPG
Error: [minor] Bad PreviewIFD directory - jetty-pano-DSC_0137-1.JPG
Warning: Truncated PreviewIFD directory. IFD dropped. - jetty-pano-DSC_0138-1.JPG
Error: [minor] Bad PreviewIFD directory - jetty-pano-DSC_0138-1.JPG
Warning: Truncated PreviewIFD directory. IFD dropped. - jetty-pano-DSC_0139-1.JPG
Error: [minor] Bad PreviewIFD directory - jetty-pano-DSC_0139-1.JPG
0 image files updated
4 files weren't updated due to errors
Right. Gimp has corrupted the Nikon PreviewIFD.
Use the -m option to ignore this problem.
Google Photos doesn't have a problem with this because it doesn't even know what a Nikon PreviewIFD is. (Ignorance is bliss.)
- Phil