Bug report

In Jupyter notebook with %matplotlib notebook:
Code for reproduction

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.plot([1,2])
fig.savefig('test.png')

I used a screenshot below instead of the file 'test.png' because the odd background only shows up in preview, which evidently uses a light gray background instead of the usual white.
Actual outcome

Expected outcome
I expect the white figure background that results in the above example when saving a pdf, or when using a different backend.

Matplotlib version

• Operating System: OS X 10.12.4
• Matplotlib Version: 2.0.2+7.ge6295a4a7
• Python Version: 3.5.2
• Jupyter Version (if applicable): 4.2.1