Documentation updates.

docs/examples/mesh/plot_image_3D.py

@@ -0,0 +1,12 @@
+import numpy as np
+import matplotlib.pyplot as plt
+from SimPEG import TensorMesh
+
+n = 20
+h = np.ones(n)/n
+M = TensorMesh([h,h,h])
+
+I = np.sin(M.gridCC[:,0]*2*np.pi)*np.sin(M.gridCC[:,1]*2*np.pi)*np.sin(M.gridCC[:,2]*2*np.pi)
+M.plotImage(I, annotationColor='k')
+
+plt.show()