The device comprises a housing (30) and a slide (32) which are movable back and forth in relation to one another and parallel to a viewing window (40), in such a way as to change over the various layers of a pile of pictures (38) in a cyclic manner. The pile is located in a removable cassette (34) having an opening (44) aligned with the window (44), and passages which enable changing of the pictures. If necessary, components of the layer changing mechanism can be contained in the cassette. The cassette can be formed of the slide itself.