The image shows two black and white photographs of a man's back, likely from an early 20th-century anatomy or physical culture study. The man is nude, standing with his back to the viewer. **Image 1:** Shows the man in a natural, relaxed pose. His arms are hanging loosely at his sides. The photograph is intended to demonstrate the natural posture and musculature of the back. **Image 2:** Shows the man flexing his biceps and shoulders. This pose is intended to highlight the muscular development of his arms and shoulders. Both images are set against a simple backdrop of draped fabric, likely a curtain. The lighting is somewhat flat, typical of photography from that era. The man appears to be of a slender build. The photographs are labeled with captions: '1. Full Back, showing Natural Poise' and '2. Back, showing Muscular Development of Arms and Shoulders.'