Update README.md

Author: TommyHuang821

README.md

@@ -7,6 +7,8 @@ Example: python3 main_DarknetVisualization.py
 
 "import .cfg path" and "Result save format" can be modified in the 'main_DarknetVisualization.py' directly.
 
+Result save format: default: 'png'. However, 'pdf' is better choice.
+
 <img src="https://github.com/TommyHuang821/Visualization-for-Darknet-network-structure-/blob/master/fig/de1.png" width="60%" height="60%">
 
 # Output Example