To edit image values we use a package called Numpy. This lets us manipulate images as if they were a N-dimensional array. The online documentation can be found here.
Go to http://sourceforge.net/projects/numpy/files/NumPy/1.6.0/
Mac users download and run numpy-1.6.0-py2.7-python.org-macosx10.3.dmg
Windows users download and run numpy-1.6.0-win32-superpack-python2.7.exe
- You can also choose to install from source (take a look at userguide.pdf at the link above).