Grounds for Chess Art

Before scrolling down, can you guess what technique was used to create this image? Photograph, digital drawing, something else?

Back to G4S! © Flickr user John under Creative Commons.

The description said,

Yesterday I returned to one of my favorite places in the world: Grounds for Sculpture. As the name implies, it's a large sculpture park, in Hamilton, NJ. I've only begun to edit the photos.

File it under 'chess sculpture'.