Will Picasa run with XFCE, Blackbox, or another Window Manager?
Yes. The core functionality of Picasa should work well with any Window Manager, though some desktop-integration features may not work with all environments. These features — automatic camera detection, setting the wallpaper, creating a screen saver, and using the native email client, for example — usually require KDE or Gnome. We’ve also provided the means for advanced users to customize Picasa for their particular environments. If you refer to the files in /opt/picasa/desktop/, you’ll see examples of how to tailor Picasa to your own environment.