I'm using J2.5.8, CB 1.9
Installed and tested CB Gallery 1.2.2

Install was generally silent, no progress messages at all. Two black/bold messages briefly describing the plugin, then the blue CONTINUE...

On testing the Gallery as a profile tab, every upload ended with "Gallery repository could not be created! Please notify system admin!"
Googling this, I found a nant answer about a missing folder under images/comprofiler - indeed, /plug_profilegallery was missing.

I created the missing folder by hand, and now the plugin works, with one exception. Each user folder underneath /plug_profilegallery is supposed to have a blank index.html file. That file is missing. While it's not a huge security hole, in reviewing the code, the plugin is supposed to copy index.html to each new user folder.

Clearly, the plugin install process failed to create the /plug_profilegallery folder and populate it with index.html

Also, the plugin, itself, fails to copy the index.html file as well.

NOTE: I also installed the plugin cbfilefield ver 1.6, which has the same behavior - e.g. it's own folder under images/comprofiler/ and a separate user folder under that. it installs and works perfectly.

krileon -
Folder permissions were the first thing I checked. The default folder permissions are 755.
Two reasons I don't suspect the server config:
1. When I manually created the needed plugin folder, the gallery worked fine.
2. I installed the cbfilefield plugin, and it installed fine, and works fine.

If I have time, I'll trace the installer on a new J25 instance and see where it's falling over. As I said earlier, there were no progress messages or errors reported during install, which (according to the install code) shouldn't happen...
Fred

To answer your specific question:
images/ is 755, and images/comprofiler/ is also 755.

I installed on a new site (same hosting company) - exact same result.
Have screenshots (but can't attach them to this posting...)