Display device for displaying images, in particular pictograms, - having an image memory, wherein image data of various images can be stored in the image memory, - having a display means for displaying an image stored in the image memory, - having a processing means with which image data of one of the stored images can be read out from the image memory and converted into an electrical signal for controlling the display means for displaying the image, - having an input for reading in the instruction for selection of the image which is to be read out from the image memory and displayed by the display means, characterised in that - each of the images stored in the image memory has an identifier with a specific brightness value and/or a colour value at a specific location of the display means or image which is always the same in all images, - the display device has at least one detection means (S1 to S4) which is a brightness sensor or a colour sensor with which an identifier of the image displayed by the display means at the specific location of the image or the display means can be detected as information about the displayed image, - the specific location of the display means is covered by a frame enclosing the display means, wherein the at least one detection means (S1 to S4) is arranged at least partly between the frame and the display means or is arranged at least partly in the frame. - the display device has at least one comparison means with which the information about the displayed image detected by the at least one detection means (S1 to S4) can be compared on the one hand with - the instruction read in via the input or - information contained in the instruction or - the stored image data or - information stored with the image data and associated with the image data on the other hand in order to recognise the displayed image. - having an image memory, wherein image data of various images can be stored in the image memory, - having a display means for displaying an image stored in the image memory, - having a processing means with which image data of one of the stored images can be read out from the image memory and converted into an electrical signal for controlling the display means for displaying the image, - having an input for reading in the instruction for selection of the image which is to be read out from the image memory and displayed by the display means, characterised in that - each of the images stored in the image memory has an identifier with a specific brightness value and/or a colour value at a specific location of the display means or image which is always the same in all images, - the display device has at least one detection means (S1 to S4) which is a brightness sensor or a colour sensor with which an identifier of the image displayed by the display means at the specific location of the image or the display means can be detected as information about the displayed image, - the specific location of the display means is covered by a frame enclosing the display means, wherein the at least one detection means (S1 to S4) is arranged at least partly between the frame and the display means or is arranged at least partly in the frame. - the display device has at least one comparison means with which the information about the displayed image detected by the at least one detection means (S1 to S4) can be compared on the one hand with - the instruction read in via the input or - information contained in the instruction or - the stored image data or - information stored with the image data and associated with the image data on the other hand in order to recognise the displayed image.