title: Reading and writing images with Mahotas
body: <p>I'm trying to write an image with Mahotas and finding it strangely difficult.</p>
  
  <pre><code>img = mahotas.imread('foo.png', True)
  mahotas.imsave('bar.png', img)
  </code></pre>
  
  <p>the error I'm gettings is:</p>
  
  <pre><code>ValueError: mahotas.freeimage: cannot write arrays of given type and shape.
  </code></pre>
  
  <p>I'm on OS X and used brew to install freeimage.</p>