Python Image Library: AttributeError: 'NoneType' object has no attribute XXX

My problem was that PIL was not installed correctly. When trying to read a png I'd get that error. My compilation summary yielded

--------------------------------------------------------------------
PIL 1.1.7 SETUP SUMMARY
--------------------------------------------------------------------
version       1.1.7
platform      linux2 2.7.3 (default, Apr 21 2012, 01:05:55)
              [GCC 4.6.3]
--------------------------------------------------------------------
*** TKINTER support not available
*** JPEG support not available
*** ZLIB (PNG/ZIP) support not available <===============
*** FREETYPE2 support not available
*** LITTLECMS support not available
--------------------------------------------------------------------

I then opted to "pip uninstall pil" and used the Synaptic Package Manager instead. That fixed it.

With googling I found this comment on SO, stating that PIL is sometimes 'lazy' and 'forgets' to load after opening. So you have to do it like this:

import Image
img = Image.open('IMG_0007.jpg')
img.load()
img.split()

Please +1 also the original comment! This person did the real work.