The photo represents students near a river. It seems thatthey are having a class in the middle of nature. The girl in the foreground is taking notes. We can imagine that ‘schools of the wild’ are about the natural world. Classes probably take place outside / in the outdoors. We can suppose that the students learn about nature by obser-ving it. Maybe the study of the environment is part of their curriculum. Maybe they have a special curriculum about / based on the (study of the) environment.