The illustration may perform either one or both of two functions. It may be a picture picture used to attract attention or it may be an "illustration" and a real aid to perception by assisting the text to tell the story which is to be presented. In the first case it would have been called an irrelevant painting; In the second case it is relevant. There have been several investigations carried on to determine the relative attention value of relevant and unlawful illustrations. Although the results so far, reached are not so decisive as may be desired, yet it looks certain that the attention value of relevant illustrations is greater than had been supposedly and that the irrelevant "picture" is frequently not so potent in attracting attention as a Relevant illustration would be. Under these circumstances it seems that, in general, the illustration in an advertisement should have the double function of attracting attention and assisting perception. Which one of these functions is the more important might be a profitable question for discussion, but when these two functions can be united in the same illustration, its value is enhanced twofold. Irrelevant illustrations are produced purely because they are expected to attract attention, when in reality they may attract the attention of no one except the person who designed them and of the unfortunate man who has to pay for them. There are many illustrations produced and inserted in advertisements because they are supposed to assist the perception. They are supposed to tell the story of the goods advertised and to be a form of argumentation. The designer of the illustration and one familiar with the goods knows what the picture stands for, and so for him it is a symbol of the goods and tells the story of the special advantages of the goods. To one unacquainted with the illustration and with the goods advertised, the illustration is no illustration at all. Not only that, but an illustration may distract the viewer from the actual message. Things animated graphics may actually draw the eyes away and the viewer will never get back to the actual message.
The advertiser is so familiar with what he has to offer that he can not appreciate the difficulty the public has in getting a clear and complete perception by means of his advertisements of the goods advertised. It is almost impossible to err on the side of clearness. A sketchy illustration may appear artistic to the designer, but there is danger that it will be taken as meaningless scrawls by the viewer, and so it will not receive a second thought from them. The text and the illustration should, first of all, be clear and should in every way possible assist the mind of the possible customer in forming a correct idea of the goods being exploited. This is what the Psychology of Advertising is all about; Getting the viewer to remember your product and purchasing it.