A further complication is the fact that Google App Engine uses Python version 2.5 (and not the default 2.6 that comes with Snow Leopard). If you just need PIL for Django, you can ignore the 2.5 references (i.e. python2.5 becomes python).

Here’s how I got it working on my machine (the steps are a combination of others’ blog posts, but main credit goes to Michael Richardson‘s post):

1. Download the latest libjpeg .tar.gz (version v7 at time of writing): http://www.ijg.org/files/.
2. Download the latest PIL version for Python 2.5 (v1.17 at time of writing): http://www.pythonware.com/products/pil/
3. Extract libjpeg and do the standard install affair:
export CC="gcc -arch i386"
./configure
make
sudo make install
from within the directory. The first line is the gem that many other blog posts leave out (and it assumes you’re using BASH)
4. Extract the PIL and change in to that directory.
5. [optional] libjpeg will have been installed in /usr/local/lib/, by default, above. Normally this directory will be picked up automatically by the PIL install below, but just for good measure (or if you have problems later in the PIL install), edit the setup.py, look for the line
JPEG_ROOT = None
. Change that line to
JPEG_ROOT=libinclude( "/usr/local" )
and save it.
6. Install PIL by running
sudo python2.5 setup.py install


That was enough to get it running for me. I can start App Engine (I use the Google-provided launcher), and use the Image API.