The picture identity element serves to compare pictures. When doing this, it is not the picture areas that are evaluated, but only the fact, that data objects of the picture type are identical. One or more pictures can be entered. The comparing takes place from the top downwards. The element will return a logic validity flag in case all pictures are identical. A special case is comparing one picture. The picture is compared with an empty picture, for instance in case of investigating, whether a valid picture has been readed from a file.