I'm talking about pictures that show technical concepts. Each day at our clients, we use whiteboards and Visio diagrams to explain difficult concepts to others, technical and non-technical. A few things that might not be obvious to you:
1. The picture INFERS 1000 OTHER words. Depending on the person's background, what experience they have with the existing systems and what their expectations are for the new system of which you may be explaining a component, the result that ends up in the person's head might be very different than what you intended. As such, you need to make sure you are thinking about this when you are drawing the diagrams
2. The picture RECALLS 1000 words. After you are done drawing a diagram, you should think of the result in the person's head as the result of both the DIAGRAM AND THE CONVERSATIONS. As such, when the person sees the diagram in again, they won't just be seeing what is statically depicted on the diagram, they'll be remembering the entire conversation and how you said data flowed from one piece to the other as you drew the diagram
3. A drawn picture CAPTURES 1000 OTHER words. More than 1000 words are created if the viewer sees the picture being drawn. If you have ever created a really complex diagram, you know this is true. If you can sit down with a person and draw the diagram piece by piece while explaining each piece, you will have a much better chance of them remembering and understanding than if you give them the fully created diagram and try to explain it. More often than not, people are overwhelmed by the complexity and can't get past it.
4. A picture AVOIDS 1000 words. Sometimes it doesn't matter what the words are. Sometimes, your objective is to just show the viewer that “it's complex” and “I know what I’m doing”. In that case, showing them a fully laid out diagram is better. They don't want to know or understand the details, they just want to know you do and you have it covered. This is a useful strategy at times.
5. A picture GUARANTEES 1000 words. If you want the same 1000 words, don't change the picture. I've seen this done many times. You are in a room with a person explaining a concept and you draw a diagram on the board. Then, you go back and formalize it into a Visio diagram. You figure out some new information that makes you draw the diagram differently (you drew systems horizontally on the whiteboard, but vertically in your Visio). This is bad b/c you are losing all the words and the viewer has to start over from scratch again (see #2 & 3). If you want the viewer to make the connection and remember all the concepts you talked about when you first drew the diagram for them in person, you need to make sure the diagram is fundamentally relatable to what they are seeing in the formal/Visio version.