If you're using the Python Imaging Library (PIL) on Mac OS X, you may get the following error:

  File "/Library/Python/2.6/site-packages/PIL/Image.py", line 1483, in show
    _show(self, title=title, command=command)
  File "/Library/Python/2.6/site-packages/PIL/Image.py", line 2123, in _show
    apply(_showxv, (image,), options)
  File "/Library/Python/2.6/site-packages/PIL/Image.py", line 2127, in _showxv
    apply(ImageShow.show, (image, title), options)
  File "/Library/Python/2.6/site-packages/PIL/ImageShow.py", line 41, in show
    if viewer.show(image, title=title, **options):
  File "/Library/Python/2.6/site-packages/PIL/ImageShow.py", line 66, in show
    self.show_image(image, **options)
  File "/Library/Python/2.6/site-packages/PIL/ImageShow.py", line 85, in show_image
    return self.show_file(self.save_image(image), **options)
  File "/Library/Python/2.6/site-packages/PIL/ImageShow.py", line 81, in save_image
    return image._dump(format=self.get_format(image))
  File "/Library/Python/2.6/site-packages/PIL/Image.py", line 488, in _dump
    self.load()
  File "/Library/Python/2.6/site-packages/PIL/ImageFile.py", line 189, in load
    d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
  File "/Library/Python/2.6/site-packages/PIL/Image.py", line 385, in _getdecoder
    raise IOError("decoder %s not available" % decoder_name)
IOError: decoder jpeg not available

This message appears because PIL was unable to find jpeg library when it was installed. Here's how to fix the error:

Download and install zlib:

curl -O http://www.zlib.net/zlib-1.2.3.tar.bz2
tar -zxvf zlib-1.2.3.tar.bz2 
cd zlib-1.2.3
./configure
make
sudo make install

Download and install libjpeg version 6a or 6b. As of January 2010, the only version available on Independent JPEG Group's website is version 8. As I found out, version 8 is not compatible with PIL 1.1.7. Luckily, I was able to find a copy of the library on Google Code.

curl -O http://google-desktop-for-linux-mirror.googlecode.com/files/jpeg-6b.tar.gz
tar -zxvf jpeg-6b.tar.gz
cd jpeg/src
./configure
make
sudo make install

Finally, reinstall the Python Imaging Library, making sure to update the library pointers.

cd Imaging-1.1.7
sed -i -e 's/JPEG_ROOT = None/JPEG_ROOT = \"\/usr\/local\/bin\"/g' setup.py
sed -i -e 's/ZLIB_ROOT = None/ZLIB_ROOT = \"\/usr\/local\/include\"/g' setup.py
python setup.py install

Posted by J.P. Cummins ● Comments (0)