Abstract: An image display unit 10 comprises a light source 14 and a light diffusing panel 18, over which is mounted an opposed pair or retaining sheets 20 with a volume 22 formed between each retaining sheet 20 and the panel 18 for receiving an image-bearing sheet 34. An elongate opening 26, 28 for providing access to the volume 22 formed in each face of the unit 10 is located spaced from the edges of the unit 10, so allowing a user to access the volumes 22 regardless of proximity of the edges of the unit 10 to other units, or to a wall or the like.