import matplotlib.image as mpimg
img = mpimg.imread("black.png")
import seaborn as sns
plot = sns.distplot(df['Rating'], hist=True, kde=True,
bins=int(15), color = 'darkblue',
hist_kws={'edgecolor':'black'},
kde_kws={'linewidth': 3})
plot.imshow(img,
aspect = plot.get_aspect(),
extent = plot.get_xlim() + plot.get_ylim(),
zorder = 0.5)