To judge by artists' renderings over the last three or four centuries, you'd think swings were invented solely for ladies to show off their legs (and so forth) COMPLETELY by accident.  The model here is laughing from sheer joy at being out in nature, NOT at the way the camera is pointed up between her knees.  Nothing written on this 3 1/2 x 4 inch glossy to tell us who or when or where but the whole thing is WAY too well done to be the work of a lucky amateur