This patent describes an alternative form of user interface for operating a device such as a camera comprising a card which is inserted in a machine. On the face of the card is contained a visual representation of the effect the card will have on the output of the machine. Preferably the camera device is capable of transforming a sensed image substantially in accordance with the transformation of a standard image comprising the visual representation and the transformation of the sensed image is printed out on the printer. Alternatively the machine comprises a book reader and the card includes a books contents for display by the book reader as indicated by the visual representation on the front of the card. On one surface of the card, the visual representation of the effect is displayed, and on a second surface, an optically encoded representation of the effect able to be read by a sensing device of the machine and decoded so as to produce the effect.