One of the most difficult things to do is to describe to someone how to put something together or how to operate a device. How do you communicate to someone the procedure to put parts together to build a plane, boat, or car? Or how do you put the pieces of a table or chair together? For objects such as Lego pieces, images are constantly used rather than text as that seems to be the easiest way to communicate to the target audience (mainly children – but I do like them as well). So why don’t we always use pictures? We can label each item numerically or alphabetically and just say to insert A1 to B1 and B1 to C1 and work our way to the end of the alphabet and then begin again with A2 to B2 and B2 to C2. Everything remains in sequence. But what if you needed to turn B2 at an angle to fit into A2 or how do you indicate the procedure to screw or hammer the bolt or nail A1 to B1? Can a picture show that? Using only images can work in certain cases, but for other situations, it would be more advantageous or easier to communicate the instructions via images and text. Images (drawings, cartoons, stick figures, etc) alone, can convey certain instructions but you need to be constantly imaginative. If you are not, the easiest way would be to describe the procedure and apply an image.
Look at a toaster manual. I cannot think of one appliance that we have purchased that does not have a manual minus text and images, such as, the toaster manual. Notice that even before we are told how to operate the toaster, or how to plug the toaster into an outlet, we are given warnings with what not to do. All critical information is always towards the front after the introduction section. The technical writer realized that there was a danger involved in using the appliance and decided to place the warnings up front. Notice that the warnings are not just plain text. They have a special warning icon as well as being denoted in a different font. How can the warning have been displayed via images alone? The next section within the manual (following the precautions) contains diagrams of all the mechanical parts that the consumer needs to be aware of for the operation of the toaster. Again, text and images are used.
I know I chose a simple devise, to develop a question or a point, but what if we were describing the use of a more complicated piece of equipment? And what if we were to distribute this device globally? How would we be able to illustrate how to operate it?
As technical writers we always have to remember to communicate the essentials in a simple and appealing format. So I think in most cases, you need both images and text, but yes there are cases where only images do work. What do you think?