Issue 1877: Fix `_to_png` when using `fit_bounds` by hansthen · Pull Request #2135 · python-visualization/folium

Previously all the images were generated against a full screen version of the map, even if the code contained a fit_bounds statement. We need to decide if this is a feature or a bug.

Indeed a breaking change, but in a way to_png was always an experimental feature, so I'm fine with the updated behavior that, IMO, is better.