because byzantine thought icons led to idol worship that was forbidden from god
You confuse Leo III (the Byzantine Emperor), who banned icons, with Pope Leo the Great (or the first), who defended them!
Leo III
Icons
According to the tradition between 726 and 730 the Byzantine Leo III ordered the removal of an image of Christ, prominently placed over the Chalke Gate, the ceremonial entrance to the Great Palace of Constantinople, and its replacement with a cross. Leo saw image veneration as a craft of idolatry and forbade the veneration of religious images in a 730 edict This did not apply to other forms of art, including the image of the emperor, or religious symbols such as the cross. He did not consult the church. This led to a clash with the Patriarch of Constantinople, who was a supporter of icons (an iconodule). It is likely that the controversy over the icons started in the provinces of the empire before Leo's actions.
He forbade the use of icons
The name of people that supported Leo lll decison are known as Iconoclasts
Leo III changing the law about icons
Byzantine Emperor Leo III forbade the use of icons in 730 primarily to promote the idea of iconoclasm, which emphasized a more abstract form of worship and sought to eliminate what he viewed as idolatry. He believed that the veneration of icons could lead to the worship of the images themselves rather than God. In response to Leo's order, Pope Gregory II strongly opposed the iconoclast movement, defending the use of icons and asserting the authority of the papacy against the emperor's decree, which contributed to a significant rift between the Byzantine Church and Rome.
Leo III changing the law about icons
The ban on icons, known as Iconoclasm, sparked significant debate within the Byzantine Empire, dividing the populace between iconoclasts, who supported the ban, and iconodules, who opposed it. The controversy was rooted in differing interpretations of religious doctrine, with some viewing icons as essential to worship and others as idolatrous. This conflict over the role of images in Christianity not only affected religious practices but also had political implications, contributing to tensions between the church and state. Ultimately, the iconoclast policies led to a protracted period of strife and debate within the empire.
In 730, the Byzantine emperor Leo III banned the use of icons. Icons are religious images used by Eastern Christians to aid their prayers.