For those on OSX, I used the following binary to get libpng and libjpeg installed systemwide:
Because I already had PIL installed (via pip on a virtualenv), I ran:
pip uninstall PIL
pip install PIL --upgrade
This resolved the decoder JPEG not available
error for me.
UPDATE (4/24/14):
Newer versions of pip require additional flags to download libraries (including PIL) from external sources. Try the following:
pip install PIL --allow-external PIL --allow-unverified PIL
See the following answer for additional info: pip install PIL dont install into virtualenv
UPDATE 2:
If on OSX Mavericks, you'll want to set the ARCHFLAGS
flag as @RicardoGonzales comments below:
ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install PIL --allow-external PIL --allow-unverified PIL