From superman.nu: Supermanica
In January 1941, Superman devises the Krypto-Raygun, a startling invention with which he can snap pictures; they are developed inside the body of a mechanism (which is in the shape of a raygun), and can be flashed upon a wall! Superman uses the Krypto-Raygun—a combination of still camera, developing mechanism, and projector—to accumulate incriminating photographic evidence of illegal gambling taking place at the Preston Club (Act No. 32, Jan 1941: "The Preston Gambling Racket!").