保存图片的时候设置参数bbox_inches = 'tight'，如：

plt.savefig("Matplotlib/graph.png", bbox_inches = 'tight')

以下是bbox_inches参数介绍：

bbox_inches：  str or Bbox, default: rcParams["savefig.bbox"] (default: None)

Bounding box in inches: only the given portion of the figure is saved. If 'tight', try to figure out the tight bbox of the figure.

参考

  • [1] https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.savefig.html