Thank you Dick for the talk tonight ( so much as I was able to stay for ) - your enthusiasm for linux advocacy and outreach was recognizable; and I enjoyed romping around your website - I wonder if your Canopus star-tracker work in the 60s had any outputs still in use on the Voyagers (some 14.6 billion miles away now...)!
Sorry I had to leave early, but I arrived home interested to check it out.  I use TinyCore linux on my daily driver laptop (Dell Latitude (c) 2012), which didn't have fotoxx in its package manager - so I built it from the source packages on 
https://kornelix.net/fotoxx/fotoxx.html. Incidentally, there is a LONG OVERVIEW section on that page which combined with your talk offered me more description of the features.  Once I built it I began checking it out.  It absolutely suggests a talented and devoted developer; it is quirky and polished in my novitiate eyes.  First off - from the building side - I observe it is a collection of executables - Michael Cornelison the author certainly has been hard at work - cloc says:
github.com/AlDanial/cloc v 1.95  T=1.51 s (33.2 files/s, 118058.5 lines/s)-------------------------------------------------------------------------------Language                     files          blank        comment           code-------------------------------------------------------------------------------C++                             31          38465          16842         118237C/C++ Header                     4            540            230           2798make                            11            111             60            634Text                             1             11              0             47CSS                              3             35             33             19-------------------------------------------------------------------------------SUM:                            50          39162          17165         121735------------------------------------------------------------------------------- 
It wasn't difficult to build - I made it into a TinyCore Linux package and then loaded it up.  Initially it attempted to tackle my entire drive, but crashed (a corrupt PNG took it down during the indexing); I then aimed it at a media specific folder, and I was surprised to see it creating thumbnails for mp4 movies - ultimately these files are just easily launched into VLC by a keystroke.
Things I like - I like the Map view - I like seeing the thumb-tack indication of where my photos' geotags point. I like the Gallery's balance between fast thumbnails and some brief metadata - and I like that folders are shown with a count of inner images and folders -a nice sort of bread crumbs.  I also like the prepackaged set of effects and filters - For instance Voodoo 1 applied to one of my photos created a nice effect.  I'm sure these features bring powerful image editing techniques into more hands more easily than something with a steeper learning curve (say GIMP).
I'm not sure it is about to become my go-to software though.  I have been a long time GIMP user and so appreciate the skill I already possess therein.  However, it does remind me that I desire a better gallery experience - formerly I used to use F-Spot Photo Manager, but that seems to be in-between working builds for some time ...  So, I am not sure what my next step will be, but I again thank you for tonight's romp through Fotoxx!
Best of Wishes,
Lexi