Known Issues

Author: Sidnei da Silva
Date: $Date$
Version: $Revision$
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Here you can find a list of known issues, contributed by users and developers. We will try to keep this list always updated with the current development and summarize the discussions on the mailing list.


ImageField generates "Decoder jpeg not available" error on OSX.

Author:Gabriele Bozzi


You are under OSX and installed Plone binaries. You have been fascinated by Archetypes and its easy way of managing document types. Your custom Schema includes an ImageField occurence for your next wonderful web project. But there is a problem: if you try to create an instance of the newly defined Archetype OSX returns you with the following annoyance:

- Decoder jpeg not available -

Grrrrrr !!!! It took me all my Biblical patience not to give up immediately (OSX is not what I would call the most plain Unix implementation.. But I love it !).


The current OSX Plone binary distribution (at writing time: 1.0.1) is a complete standalone framework including Python 2.1.3 and its libraries. Even if the Python distribution is quite complete, it does not seem neither to include the necessary Pyhton bindings for the PIL (Python Imaging Library) nor the classic (read standard.) Zlib extensions. The reason for this is maybe because OSX does not include as standard the following libraries: IJG Jpeg Library and zlib.

The IJG Jpeg Lib is a general purpose library that provides C code to read and write JPEG-compressed image while Zlib is the GNU zip library.


Install from source Jpeg and Zlib libraries and recompile the PIL against the Python that came in the binary OSX distribution.

I will report here just my experience on how I let things work hoping that somebody having the same problems could find a solution.


  1. Download Zlib sources from

  2. On a temporary folder, for example:

  3. Open a shell and put yourself in the folder mentioned above; perform the following commands (you can use sudo as listed or just log-in as superuser):

    tar xfz zlib-1.1.4.tar.gz
    cd zlib-1.1.4
    sudo make install

If everything went well you should exit with no error codes from the compilation and install sequence. Zlibs are installed in /usr/local/ and /usr/include.

Jpeg libraries

  1. Download jpeg sources from

  2. On the same temporary folder as before and perform the following operations:

    tar xfz jpegsrc.v6b.tar.gz
    cd jpeg-6b
    make test
    sudo make install
    sudo make install-lib

    This time the process is a bit longer but, again, you should not have any relevant error (if you have a stock-configured OSX) except the one mentioned later.. Check if the following files are present:

  3. To avoid OSX to complain for having libraries not updated (if it did not already complain at the end of the install-lib step):

    ranlib /usr/local/lib/libjpeg.a


This is the last step and, to a little extent, the one that needs just a few tweaks.

  1. Download PIL sources from 1

  2. Again, perform from the temporary folder the following commands:

    tar xfz Imaging-1.1.3.tar.gz
    cd Imaging-1.1.3
    cd libImaging
  3. After ./configure analyzed our OSX and generated the necessary rules for make to work we need to edit the resulting ImConfig.h file. I use vi for the "quick-and-dirties" but feel free to use whatever editor you like:

    vi ImConfig.h

    And change the following line:

    #undef HAVE_LIBJPEG

    in the following:

    #define HAVE_LIBJPEG 1

    Check also if the line:

    #define HAVE_LIBZ 1

    is present (it should). If not add it at the end of the file.

  4. Save it and go on with the following shell commands:

  5. Make will complain with a warning:

    ranlib: file: libImaging.a(Dib.o) has no symbols

    Never mind and continue: it does not seem to be critical.

  6. Now perform the following commands 2:

    cd ..
    PloneDirectory/ Python/bin/python build
    PloneDirectory /Python/bin/python install
  7. You are done! To test the whole thing just perform this:

    cd ..
    PloneDirectory/ Python/bin/python ./Minitest/
[1]As for the previous packages I am mentioning versions that are tested to work with Binaries 1.0.1 of the Plone distribution. Check which version you have in the future to avoid potential incompatibilities.
[2]PloneDirectory is the actual folder where your Plone has been installed.

For good measure I suggest to restart the machine (it's not really needed but I still wonder how OSX does not get confused with framework and classic libraries.. If you are not on a production server (I guess you are not) you should have no problem doing this.

A lot of valuable resources and help can be found on the python image sig mailing list where I found a message from that helped me much to verify my steps (initially I adopted another approach but he gave me the "Satori" to rationalize the installation). I would be delighted to credit him for this paper along with me if I only knew the name of the guy (too lazy to contact him !!?).

Happy Scheming with Archetypes (this product is just wonderful, I hope it will be included in the next version of Plone).