import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
X = 10 * np.random.rand(5, 3)
fig = plt.figure(figsize=(15, 5), facecolor='w')
ax = fig.add_subplot(111)
ax.imshow(X, cmap=cm.jet)
plt.savefig('image.png', bbox_inches='tight', dpi=100)
Resize a figure automatically in matplotlib