Picasa-Downloader – A simple Python script to get the normal size images
https://github.com/anoopjt/Picasa-Downloader
pip install BeautifulSoup
cd ~/Downloads
wget https://raw.github.com/anoopjt/Picasa-Downloader/master/picasa_downloader.py
Pycasa – capable of downloading full size images
http://code.google.com/p/pycasa-download/
This open source software includes a GUI. It relies on PyGTK and it is therefore difficult to get it to work with Mac OS X.
This workes on Ubuntu Linux (I already have the PyGTK packages installed, if you haven’t this might complain about it):
cd ~/Downloads
wget http://pycasa-download.googlecode.com/files/Pycasa-1.0.tar.gz
tar -xf Pycasa-1.0.tar.gz
cd pycasa
./Pycasa.py