Some more links you might want to add:
Sorry for the formatting but: “Sorry, new users can only put 2 links in a post.”
Thanks, adding those now. 
Done!
Along side Argyll CMS, you might want to add Color Hug, an open source hardware and software color management solution.
For geotagging, Robert Bruce Park’s “Gotten Geography”: lp:~robru/+git/gottengeography : Git : Code : Robert Bruce Park
For workflow, Vincent Vande Vyvre’s “Oqapy” http://www.oqapy.eu/
The ColorHug is only a simple piece of hardware (and the results are not that great in some cases). The software you want to use with it is colord and some frontend, like gnome-color-manager or kde-colord.
It would be great to have a Geo-location tools category, such as GeoSetter, included.
(If there is any concern about Free Software vs. Freeware, please note that, while the source code for GeoSetter is apparently not available, there is clearly no charge for the use of the software nor is it a “lure” to a more advanced or capable paid package. The FSF definition of Freeware vs. Free Software, though useful, is a bit fuzzy in cases where the author would appear wish to retain the rights to his source code and/or would accept a donation if offered. ExifTool is a good example of where the author has made it know that he would accept donations if offered.)
The link is http://www.geosetter.de/en/.
GeoSetter is a freeware tool for Windows (XP or higher) for showing and changing geo data and other metadata (IPTC/XMP/Exif) of image files (e.g. images taken by digital cameras).
I’ve noted that nobody has listed a freeware version of a standalone DAM (Digital Asset Management) system.
Hope that someone has come across one and will list it for inclusion as a category.
Just a note to say that the link for gottengeography didn’t work for me. Perhaps the link I used will help: https://launchpad.net/~gottengeography.
That’s freeware, not free software. 
Darktable has a few geo features too, including a map and a way to geotag photos using a GPX file.
I think this thread belongs in Software, pinned to the top, not in Processing.
Please update the link to geeqie. The current website is geeqie.org, on sourceforge everything except mailing lists is deprecated. Thanks.
exiv2. Considering that it is the background metadata tool used by most apps, I think it deserves a place on the list.
I’ll fix the link there to point to the right place, thanks for the heads up! 
[Edit]: Updated!
I’ll add exiv2 to the list as well! Is there any stand-alone interface that a casual user might be interested in using? I only ask because I’m trying to keep the list relevant to photographers first, who may not care about libraries and background infrastructure (vs. their normal interface to these things). (It’s the same reason I haven’t put rawspeed or libraw on the list for instance).
Does Geeqie have an “official” icon I can use on the page as well?
(sorry, this was meant for @rasimo)
I use the CLI all the time
CLI works great for me! (Heck, I’ve been using Phils exiftool for years this way anyway… ). I’ll get it added in right away - thank you for the heads up!
What about adding smaller, simpler web gallery solutions? I love fgallery for its simplicity. It’s a web gallery generator including suitable companion files (css, js etc) and generates modern, beautiful yet simple galleries that focus on the pictures. Together with a suitable .htaccess and .htpasswd file it’s an easy solution to share family photos etc. on my own web server.
Yes there is, you can find it in the git repo:
http://geeqie.org/cgi-bin/gitweb.cgi?p=geeqie.git;a=blob;f=geeqie.png;h=1529f5d21e8bf9a2b47f39712af4787fe18f39ca;hb=refs/heads/master
Thanks for updating!
Perfect, thank you! I’ve updated the entry on the Software page to include the icon + the text from the page:
Geeqie is a lightweight image viewer for Linux, BSDs and “compatibles”.
Why on earth is the icon not shown on the project page anywhere?