Proportion is the harmony an image has in relationship to each of its elements. Character art is a great way to look at proportion. Often video games and cartoons develop character designs that emphasize disproportional anatomy: over-sized hands, feet, and heads. This warping of proportion creates its own style that works in context of making characters stand out on screen. In general, though, proportion is going to be more constrained. Artists often use what is called the Rule of Thirds, which is a way of dividing the image space so that proportions can be accurately estimated. Think of the image space divided into nine equal blocks. Now we have a better reference point to ensure proper proportions. Another visual example of proportion is the nautilus-like triangle graph.