python - Decoder JPEG not available error when following Django photo app tutorial

Question

I am following a Django tutorial that involves image uploading, and have run into this problem. I tried installing and reinstalling PIL, libjpeg, and libfreetype6 several times, but nothing so far seems to be working. I have spent several hours trying to find a solution, and am very frustrated at this point. Please help.

Here is the result of selftest.py after I reinstall PIL on my mac:

PIL 1.1.6 BUILD SUMMARY
--------------------------------------------------------------------
version       1.1.6
platform      darwin 2.7.3 (v2.7.3:70274d53c1dd, Apr  9 2012, 20:52:43)
              [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]
--------------------------------------------------------------------
--- TKINTER support ok
*** JPEG support not available
--- ZLIB (PNG/ZIP) support ok
*** FREETYPE2 support not available
--------------------------------------------------------------------
To add a missing option, make sure you have the required
library, and set the corresponding ROOT variable in the
setup.py script.

To check the build, run the selftest.py script.
rrdhcp-10-32-44-157:Imaging-1.1.6 pfg$ python selftest.py
*****************************************************************
Failure in example: _info(Image.open("Images/lena.jpg"))
from line #24 of selftest.testimage
Exception raised:
Traceback (most recent call last):
  File "./doctest.py", line 499, in _run_examples_inner
    exec compile(source, "<string>", "single") in globs
  File "<string>", line 1, in <module>
  File "./selftest.py", line 22, in _info
    im.load()
  File "PIL/ImageFile.py", line 180, in load
    d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
  File "PIL/Image.py", line 375, in _getdecoder
    raise IOError("decoder %s not available" % decoder_name)
IOError: decoder jpeg not available
1 items had failures:
   1 of  57 in selftest.testimage
***Test Failed*** 1 failures.
*** 1 tests of 57 failed.

Answer 1

There are several cases with PIL which lead to a similar experience. If you have installed PIL out of a virtualenv using

pip install PIL

Then you should have installed the dev versions of libjpeg, libz before. Assuming you're on a Ubuntu box, a

pip uninstall PIL
apt-get install libjpeg-dev zlib1g-dev libpng12-dev
pip install PIL

should suffice. You could also install Pillow instead of PIL, it works better with setuptools and can be installed in a virtualenv.