Phil Harvey's ExifTool ( http://www.sno.phy.queensu.ca/~phil/exiftool/ ) is the backend of many Image Browsers/Editors and offers unbeaten power in editing Exif tags, Metadata, GeoData, Keywords and even Color Profile Embeds and Assignment. It can be used in Terminal, but like all Killer Terminal Apps, we always wish the was a GUI - Well NOW there is - for Tiger!
Contacted Marc Vos: Maker of the Mactel ExifTool GUI app "SetEXIFDATA" ( http://marc.vos.net/downloads/setexifdata/ ) because his site had a Universal Binary icon on it, and even though the current version won't start on PPC. Marc Siezed on the chance to pull his old G4 Cube out of the closet and compiled a version of this amazing app for all of us Luddite's to enjoy - and it WORKS! Add, Remove, Edit virtually any piece of an image's Metadata without having to recompress/resave it.
1st Download ) SetEXIFDATA application. (SetEXIFDATA requires ExifTool to be installed and Marc's app comes with version 10.11).
2nd Download ) ExifTool - Current Version - 10.27 (works fine on most Tiger systems).Compatibility
10.4/PPC (Not Tested on 10.3 or 10.5 - presumed to work).