title: Read in an indexed color image in Python
body: <p>An indexed color image is an image with pixels that are integers (1,2, .. N), and for each integer, an associated color maps to this pixel from a given color map.  In MATLAB, reading in an indexed color image can be done in the following way:</p>
  
  <pre><code>[im, colormap] = imread('indexed.png');
  </code></pre>
  
  <p>How can I do the same thing in Python? I have tried OpenCV, <code>scikit-image</code> but they all convert to RGB automatically.</p>