in reply to JPEG EXIF headers and Perl
I've got some good news and some bad news. The good news is that you can read the EXIF headers with Image::Info (see exifdump) or PerlMagick. The bad news is that as of right now there is not any way that I can find to write EXIF headers. PerlMagick has it on the todo list though.
See also: EXIF File Format.
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Seekers of Perl Wisdom