Other forms: iconographies
The visual symbols used to represent something are known as iconography. When an artist paints a large white lily to represent death and a small dog to symbolize loyalty, she's using iconography.
Whenever someone uses a familiar symbol or image to represent a particular person, group, characteristic, or theme, they're using iconography. In art, iconography sends specific messages, like when a lamb in a religious painting represents Jesus. In politics, iconography can convey things like strength and patriotism through flags, stars, and other symbols. The root of this word is the Greek eikon, which means "image or picture," but also "an image in the mind."