Resize a figure automatically in matplotlib

Use bbox_inches=”tight”

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)

…only works when saving images though, not showing them.