OK, I can see that 'JFIF' in the tombe.jpg file. But it turns out it's not in my file at all, only the 'Exif' header is there. Our sysadmin guys haven't installed the suggested exiftool tool yet; presumably exiftool will be capable of *adding* the JFIF header (which I gather should come before the Exif header, although apparently both headers want to be first).
You don't have to wait for sysadmins ;-) . Just get the tarball (the home of exiftool seems to be http://www.sno.phy.queensu.ca/~phil/exiftool/) and you can run the script from the tar directory. (Or by setting PATH and PERL5LIB environment variables.)
Turns out GIMP will also save it with both the JFIF and Exif headers, and that works with XeTeX, and has a batch method. So I guess I could use that.
As it as already been pointed out, be careful that the jpegs are not re-encoded. If not done very carefully, it will degrade the image quality. (Re-encoding a lossy format will loose even more information.)
best, Stefan -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex
