The retina is analogous to film in a camera.  It receives a real image and sends it to the brain.  The light sensitive layer consists of a dense array of rods and cones, which absorb the light.  The signal from rods and cones is processed by the nerve cells in the plexiform layer and relayed to the optical nerve.  The blood which nourishes the retina is carried through the blood vessels in the choroid layer.  That layer also absorbs light so it doesn't reflect back and strike rods and cones.  However, if bright enough light is shined directly into the pupil, some will come back out, and since the choroid layer is filled with blood, the light coming out will be red.  That phenomenon is known as red eye usually seen in photographs.