Load the file with pydot.graph_from_dot_file to get a pydot.Dot class instance. Then write it to a PNG file with the write_png method.
import pydot
(graph,) = pydot.graph_from_dot_file('somefile.dot')
graph.write_png('somefile.png')
Load the file with pydot.graph_from_dot_file to get a pydot.Dot class instance. Then write it to a PNG file with the write_png method.
import pydot
(graph,) = pydot.graph_from_dot_file('somefile.dot')
graph.write_png('somefile.png')