It may happen that you want to draw an image on you map. Here are example on how to do that.
In [1]:
import sys
sys.path.insert(0,'..')
import folium
from folium import plugins
In [2]:
m = folium.Map([37,0], zoom_start=1, tiles='stamentoner')
plugins.ImageOverlay(open('Mercator_projection_SW.png', 'br'),
[[-82,-180],[82,180]],
opacity=0.8,
).add_to(m)
folium.LayerControl().add_to(m)
m
Out[2]: