title: concatenate two images from plt.imsave with different cmaps without installing another package
body: <p>I'm making movies by saving a series of images, then using <a href="http://imagej.nih.gov/ij/" rel="nofollow">ImageJ</a> to put them together, as so:</p>
  
  <pre><code>for i in range(n):
      fname = 'out_' + str(1000+i)
      plt.imsave(fname, A[i], cmap=cmapA)
  </code></pre>
  
  <p>I'd like to somehow "concatenate" two images (so they appear side-by-side for example) and save, produced with different colormaps. So hypothetically:</p>
  
  <pre><code>for i in range(n):
      fname = 'out_' + str(1000+i)
      plt.hypothetical_imsave(fname,  (A[i], B[i]),  cmap=(cmapA, cmapB),  axis=1)
  </code></pre>
  
  <p>Of course, this is pseudocode, but is there some way to do this with good old numpy and matplotlib without installing a whole new package? </p>