How did the use of icons lead to a schism between the Catholic Church and the Eastern Orthodox Church?

It didn't. The Schism was for other reasons. Differences like: papal infallibility, purgatory (unscriptural), immaculate conception of Mary, Filioque (unscriptural), primacy and supremacy of the pope, indulgences, differences in the Eucharist, in the doctrine of original sin, in monastic traditions, etc. These were some of the main reasons of the Schism of East and West and the departure of the patriarchate of Rome. All the other patriarchates of Antioch, Alexandria, Jerusalem and Constantinople remained with the Orthodox Church at the Great Schism.