I need to install Google Picasa picture Viewer on ubuntu 12.04 but there is no such package for Ubuntu or any other Linux distro.
Even when it was supported by Google, what they distributed was just the windows executable and a copy of wine. This combination still works.
wine from the software center (or with
sudo apt-get install wine).
Download the latest installer and then run it by double clicking in
nautilus or running
wine picasa39-setup.exe in a terminal. This should take you through the install process and add an entry to the applications menu.
Being a windows application, it doesn't integrate that well with Ubuntu. I have found picasa 3.9 to crash occasionally in Ubuntu - anecdotally earlier versions (3.6) may be more reliable.
While it is likely to be possible to run picasa for windows under wine for the foreseeable future, you may wish to consider using a native application, such as
Good officially killed support for the Picasa Linux client back in April, 2012. Your best option is to use Picasa Web or you can use one of the many photo management apps that are available for Linux such as shotwell