Searching for a good solution to host image galeries, I came across Phoca Gallery.
Deployment was easy and I quickly could add images and organize them in categories.
Also the rights management works fine to selectively provide images to specific groups of users.
There are a lot of customization possibilities for the display. Figuring everything out may take a little, so it's worth trying the configuration on a test system and once one is satisfied with the results, porting the settings to prod (but that's the good way to do upgrades anyway ;) ).
When contacting the developer he responds fast and kind.
I use this extension on three sites now, all Joomla 3 based, and like the results very much.