The dispute about the use of icons caused conflict within the Eastern Church, as well as with the Western Church.
In the picture, Nikephoros I symbolizes the Western church and how they supported icons. Nikephoros I is standing on Patriarch John VII of Constantinople, suggesting that the ideas of the Western Church triumphs the ideas of the Eastern church. (Oh, I wonder how angry the Eastern Church would be seeing that picture).
Hope this helped and good luck in your studies! :)