Photo metadata software

Question

My mother uses some software to organize and add metadata about photos -- dates, people included, commentary, etc. She has probably thousands of photos that she has scanned and been archiving. Unfortunately, the program she has been using only exports this by creating an executable that can run on windows, which runs a viewer to see the data, and it stores all of its data in a proprietary, undocumented format. Since this is data that she wants to archive and distribute, this program is completely unacceptable.

I want to recommend to her a program to do this that is free/open source, uses an open and documented format, and preferably is cross platform. It also needs to handle various image types without converting to another format (including jpeg, tiff, etc). The data she is compiling will eventually be viewed on many platforms (Linux, Windows, Mac, maybe more), so the most critical thing is that the format be open.

Answer 1

tl;dr: Use digiKam, edit the settings so it saves metadata to image files themselves, use the caption field.

I researched this a little a few months ago. Here is what I came up with.

There are several metadata formats available for images, but the most widely used is EXIF. This is important, because I found that most programs that can edit photos or their metadata will DESTROY all metadata in formats they don't know how to use. So the best place for free-text metadata is the EXIF comment field.

As for programs to use, the best seems to be digiKam. It recognized and could edit more types of metadata than any other program I tried. The one major caveat is that it DOES NOT save image metadata to the image files themselves by default -- you have to edit your settings to achieve this. Otherwise it saves metadata to some auxiliary file that you will probably forget about and that you certainly won't distribute with the photo. Also, the EXIF comment field is labeled caption.