Picasa uninstall instructions
Uninstalling Picasa on ArchLinux is as easy as uninstalling any other applications on ArchLinux.
Simply run (as root or via sudo)
pacman -Rcs picasa
For more details on how to use pacman, please refer to the pacman manpage or the ArchLinux wiki.
Please note that Picasa has created a ~/.picasa directory for each user that used the application. This directory contains per user settings.
Pacman does not take care of removing these directories, so if you decide you do not want to keep the user settings, please remove the directory manually.