We don't know much about Bogomil theology, but of the small amount that we do know, I think there are three things that may be reflected in the imagery of the RC.
1. Adoptionism: This is a theological teaching that Jesus was born a man, but was adopted by God as His son. The circumstantial evidence for this in the RC is the fact that Jesus is normally portrayed in a way similar to other saintly people (with a simple turban-halo), but at some point (after the crucifixion?) appears to be transformed into a giant luminous being. Does this represent the adoption of Jesus by God?
Jesus riding into Jerusalem
2. Absence of Mary: One of the implications of adoptionism is that Mary would have become pregnant in the normal earthly manner, rather than through divine intervention. As a result, adoptionists like the Bogomils and Paulicans did not revere Mary in the same way that Catholics and Eastern Orthodox churches did. The circumstantial evidence for this in the RC is the fact that Mary is rarely depicted, and never given a special status.
The family of Jesus receiving the Magi
3. Dualism: In addition to being adoptionist, the Bogomils were apparently dualist, believing in the existence of an evil demiurge as a counterpart to God. Some dualists, like the Marcionists, held that the demiurge was none other than the God of the Old Testament. The main circumstantial evidence for this in the RC is the absence of clear Old Testament imagery.