Again, I just lost a precious hour trying to install the Python Imaging Library in a virtual environment on Ubuntu. Even though I had installed the required dependencies, the install script did not detect that freetype and zlib were installed… The culprit: Ubuntu installs the libraries in a very weird directory and you need to set these directories in the PIL setup.py script.

First, install the required dependencies:

apt-get install python-dev \
libfreetype6-dev zlib1g-dev libjpeg8-dev

tar -xvzf Imaging-1.1.7.tar.gz
cd Imaging-1.1.7.tar.gz
vim setup.py

Then, in the setup.py file, set these two variables

ZLIB_ROOT = ("/usr/lib/i386-linux-gnu", "/usr/include")
FREETYPE_ROOT = ("/usr/lib/i386-linux-gnu",
    "/usr/include/freetype2/freetype")

Then just run python setup.py install when in your virtual environment.