"Botticelli painted many images that include the Virgin, the Child and the angels. In this image, Mary is sitting holding the Holy Child with a heavenly light shining directly on her. Botticelli painted an oversized Mary to symbolize how her arms can support Christ. There is no visible architecture; the angels and Mary themselves become the supportive structure symbolizing that God can handle anything.
The elements of this image contain many symbolic items. Each figure wears a sad expression as if their mind is somewhere else thinking of Christ’s death. The seed of the pomegranate the infant is holding signifies that Christ will receive resurrection through rebirth just as the seed will cause the birth of a new plant. The angel in front is holding lilies and roses which are both symbols of the Virgin. That same angel is wearing sashes with the words AVE GRAZIA PLENA which mean “Hail [Mary] full of grace.”" (emphasis mine)
BE AT PEACE
Gregorian Chants: here. Text about the painting: here.