title: How to display image icons on nodes in NetworkX
body: <p>I am using NetworkX module to present the network of an infrastructure systems. In this systems, nodes and edges consist of different types of entities and I would like to use some icons representing their types instead of circle, star or square. </p>
  
  <pre><code>G = nx.Graph()
  G.add_edge('a', 'b')
  nx.draw(G, labels={'a':'img1', 'b':'img2'}, with_labels=True)
  plt.show()
  </code></pre>
  
  <p>Obviously, my script creates a graph with labels of 'img1' and 'img2'. I am looking for a way to display two icons instead of the filled circles and labels.</p>