It looks like Norman Rockwell, but it is actually Stevan Dohanos who also painted The Saturday Evening Post covers. This is from February 24, 1951.
A great historical event rarely remains standing alone. It echoes down through the generations, for good or ill. A lighted copy of this painting is in my law mines. The original painting on which this painting is based got any number of historical facts wrong, but it is true to the spirit of the event, the turning point in the American Revolution and how Washington, and the men who followed him, were indispensable for establishing our new nation.