A belly door for a gaming machine includes a frame for receiving a sheet of artwork and a light reflective chamber having an open face which is located behind the frame when in a closed position. Clamping means are provided for clamping the artwork between the frame and the chamber. A recess extends along one edge of the chamber including sockets for receiving a fluorescent light tube when the chamber is in the closed position. A diffuser panel is disposed in the chamber behind the artwork located so as to be edge lit by the fluorescent light tube. The reverse face of the panel, which in use, faces the rear wall of the chamber defines a series of white opaque dots which in use, diffuse and direct the light in a forward direction perpendicular to the plane of the panel. The size of the dots in the panel increases with the distance of the dots from the fluorescent light tube. This arrangement ensures that the light panel produces a very evenly balanced lighting of the artwork.