title: MovieWriter imagemagick unavailable
body: <p>I am trying to animate the graph, but jupyter is giving error:</p>
  
  <p>MovieWriter imagemagick unavailable.
  And just animating the 1st image(which is obvious as MovieWriter is not working). How to fix it?</p>
  
  <p>Python version: 3</p>
  
  <p>Here is the code</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  import networkx as nx
  from matplotlib.animation import FuncAnimation
  
  # number of nodes
  size = 10
  
  # generate graph
  G=nx.complete_graph(size)
  
  frame = np.random.randint(0, 5, (size, size)) # random ndarray between 0 and 5, length and number of frames = number of nodes in the graph
  
  pos = nx.spring_layout(G)
  nodes = nx.draw_networkx_nodes(G,pos)
  edges = nx.draw_networkx_edges(G,pos)
  plt.axis('off')
  
  def update(i):
      nc = frame[i] # np.random.randint(2, size=200)
      nodes.set_array(nc)
      return nodes,
  
  # output animation; its important I save it
  fig = plt.gcf()
  ani = FuncAnimation(fig, update, interval=50, frames=range(size), blit=True)
  ani.save('crap.gif', writer='imagemagick',  savefig_kwargs={'facecolor':'white'}, fps=1)
  
  </code></pre>
  
  <p>Expectation: Animation should be working and will be able to show the updated color</p>