I hate to take issue with @robtillart, but there is no need for power transistors with a servo.
You do need to have a separate power supply for the servo as the Arduino can't supply enough current unless the servo is very small AND has no load on it. If the servo draws too much power the Arduino will behave erratically which will probably appear like a software problem. Safest thing is to use a separate power supply. Just remember to connect the Arduino ground to the servo ground.
I can't figure from your photos how things are connected. Can you post a photo of a clear drawing of all the connections.
...R