Google’s Linux software repositories make it easier to download and stay up-to-date with current releases of Google Linux applications. Please choose one of the guides below to help configure your system to use these repositories.
First you need to edit /etc/apt/sources.list file
add the following line
# Google software repository
deb http://dl.google.com/linux/deb/ stable non-free
Save and exit the file
you must download the key and then use apt to install it and refresh your package indexes.
Run these commands as root:
#wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
Now you need to update the source list using the following command
Install google applications now you can see the following command to install google picasa
#apt-get install picasa