This is "A Cowherd in a Woody Landscape" by Jan-Baptist Huysmans. Painted in about 1697, the evening light catches his white shirt and the tops of the tumbling waters of a stream at his side. A slender birch tree seems to cling on to the side of the rocky slope, its tall trunk vanishing into the darkness of the woods overhead.
This mountainous landscape is imaginary, painted in the Italianate style popular in the Netherlands during the 17th century. Although we don't know if Huysmans had ever been to Rome himself, he knew artists who had and was able to refer to their sketches and drawings to create his softly lit views of the Roman countryside.
Notice how the artist uses light and shadow to create a sense of depth and atmosphere in this scene. The rocky slope and the woods overhead add a wildness to the scene that's quite captivating.
A Cowherd in a Woody Landscape hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.