Create an ultra-realistic, full-body photograph of a handsome man with an athletic build, gray hair and beard, and captivating eyes, preserving 100% of his facial features. He sits on a moss-covered rock by the edge of a vibrant turquoise lake, surrounded by lush green foliage cascading above him. He wears an open white linen shirt revealing his defined torso, matching white shorts, and sunglasses. His bare feet are lightly submerged in crystal-clear water. The scene is bathed in natural light that highlights his skin texture, facial details, hair, and the textures of the surrounding environment. Enhance all textures and colors for vivid, lifelike quality, keeping skin, hair, eyes, mouth, and nose fully realistic. Include a subtle, discreet signature “@dayno_ai” in the bottom-left corner using a contrasting color that complements the image. Convey a calm, inviting, and serene atmosphere.