Ipython notebook matplotlib gui backends dlopen import error on osx
<p>On OSX 10.11.6 using Anaconda python 2.7 when switching to (any) gui matplotlib backend from <code>%matplotlib inline</code> in jupyter ipython notebook generates:</p>

<blockquote>
  <p>ImportError:
  dlopen(/Users/.../anaconda2/lib/python2.7/site-packages/PyQt4/QtGui.so,
  2): Library not loaded: @rpath/libpng16.16.dylib   Referenced from:
  /Users/.../anaconda2/lib/libQtGui.4.8.7.dylib   Reason:
  Incompatible library version: libQtGui.4.dylib requires version 39.0.0
  or later, but libpng16.16.dylib provides version 34.0.0</p>
</blockquote>

<p>Any suggestions which one of the mentioned libraries I am supposed to install/update or both? And how to find these for OSX?</p>

<p>Problem was solved after I did this:</p>

<pre><code>conda update libpng
</code></pre>

<p>Which resulted in:</p>

<pre><code>The following packages will be UPDATED:

    libpng: 1.6.17-0 --&gt; 1.6.22-0
</code></pre>

python matplotlib pyqt4 anaconda jupyter-notebook