The deluxe solution would be to disable the menu if a non-JPEG images is active. So no one even can go in the wrong direction. Thanks, Markus
As far as I can tell, there seems no reason why PNGs can’t have region data written to and read. So the deluxe solution would be to support PNGs, and if the jAlbum libraries can’t, then to disable the option.
I think the deluxe solution would be to embed xmp metadata in more file types than just JPEG files. I've experimentally switched the commons imaging library to "PixyMeta" which supports embedding xmp metadata in the following file types: JPEG, GIF, PNG, and TIFF
To try this out, use jAlbum 20.2, then replace lib/jalbum-core.jar with this one: http://jalbum.net/download/beta/jalbum-core.jar
Finally, put the attached file inside jAlbum's lib folder. Now restart jAlbum and try adding area tags to any of these file types: JPEG, GIF, PNG, and TIFF