The authors refer to Egyptian iconography with regard to both Hatshepsut and Akhenaten. What is Egyptian iconography?

An Egyptian Iconography is a form of visual images or symbols used in their art.  

Explanation:

Iconography in an Egyptian civilization played an important role in society and art. Iconography used to show religion images along with representations of scenes from mythologies and rituals. Iconography images were carved in relief or painted on the walls of temples and tombs with images of Pharaohs and gods.