Let's break it down. The first part, Visual, is what you see when you look at something, color, arrangement, font, etc... The rhetoric part deals with the persuasion. In conclusion, it's what we see and how we act or think when we see it. It is one's ability to understand what an image is attempting to communicate.
Describing how visual images communicate, as opposed to aural, verbal, or other messages. Visual rhetoric generally falls under a group of terms, which all encompass visual literacy.
