One of the problems with Marian feasts is that they are often misunderstood; another is that they tend to attract a lot of bad art. I cannot do anything about the bad art, but a few years ago I wrote a rather dry post summarising what the Catholic Church actually teaches about the Immaculate Conception of Mary, and if your ideas about it are a bit hazy, you may find the post useful: https://www.ibenedictines.org/2011/12/08/the-immaculate-conception-of-the-b-v-m/.
It is a pity that Mary has inspired so much bad art and, dare I say it, lazy theology. Once we have grasped that everything the Church believes and teaches about Mary is meant to help us focus on her Son, all makes sense. The Syrian Fathers, in particular, are lyrical in her praise, but they, too, want us to look beyond her to God himself when they call her the ‘all-inviolate spotless robe of him who clothes himself with light as with a garment . . . flower unfading, purple woven by God, alone most immaculate.’ Now, as it happens, earlier this year Michael Peppard published a fascinating article in The New York Times, in which he argued that a wall painting from the baptistry of Deir ez-Zor, Syria, now in the Yale University Art Gallery, might possibly be the oldest extant depiction of Our Lady. I cannot reproduce the illustration for copyright reasons, but you can read the whole article here.
We are so accustomed to images of Mary with floating drapery set against Renascence skies that we tend to forget the earthliness of earlier depictions — Mary reading as the angel arrives to ask her consent to be the Mother of God; even earlier, Mary drawing water from the well as Peppard suggests is the case at Deir ez-Zor and in many icons from the Orthodox tradition. It is when we forget what I call the earthliness of Mary that we forget or misprize her true greatness. The miracle of grace we see in her shows us what our frail and often grubby humanity can become. Today’s feast is not remote or arcane. It is an encouragement and a joy, and the fact that it occurs during Advent is a reminder that God wills that all should be saved through the coming of his Son, Jesus Christ. Let us give thanks for that.