ImgMeta (2013-10-10) source code is now available for download. The author released it as public domain.

"With ImgMeta you can add your own information to any image-file, to describe them better than its pure filename can. These information (so called meta-data) are stored in the 'Extended Attributes' (EA) of the file (read more about EAs and their special considerations )."
Please remember that the software is AS IS, the author don't have any resposability for any malfunction, but he accepts feedback since this projects are still under active develomen.
Download: http://hobbes.nmsu.edu/h-search.php?key=ImgMeta_20131010.zip
URL: http://os2.zworks.de/ImgMeta/eng/index.html
Special thanks to Lutz Wagner for making the source code available.