title: Force pyplot.imshow() to produce image with higher resolution
body: <p>I have an NxN array that I am plotting in Python using <code>matplotlib.pyplot.imshow()</code>.  N will be very large and I want my final image to have resolution to match.  However, in the code that follows, the image resolution doesn't seem to change with increasing N at all.  I think that <code>imshow()</code> (at least how I'm using it) has a fixed minimum pixel size that is larger than that needed to show my NxN array with full resolution.</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  from matplotlib import cm
  
  array = np.loadtxt("output.dat",unpack=True)
  plt.figsize=(30.0, 30.0)
  im = plt.imshow(array,cmap='hot')
  plt.colorbar(im)
  plt.savefig("mandelbrot.pdf")
  </code></pre>
  
  <p>As you can see in the code above, I've tried messing with <code>plt.figsize</code> to try and increase resolution but to no avail.  I've also tried various output formats (.pdf, .ps, .eps, .png) but these all produced images with lower resolution than I wanted.  The .ps, .eps, and .pdf images all looked the exact same.</p>
  
  <p>First, does my problem exist with <code>imshow()</code> or is there some other aspect of my code that needs to be changed to produce higher resolution images?</p>
  
  <p>Second, how do I produce higher resolution images?</p>