318. In the earthly Liturgy, the Church participates, by a foretaste, in that heavenly Liturgy which is celebrated in the holy city of Jerusalem, toward which she journeys as a pilgrim, and where Christ is seated at the right hand of God; and by venerating the memory of the Saints, she hopes one day to have some share and fellowship with them. [Sacrosanctum Concilium 8]
Touring an orthodox cathedral when I was in grad school, the rector described the purpose of surrounding the assembly with icons of the saints reinforced the sense that on earth they assisted us in spiritual ways, even in our earthbound worship of God.
Thus, in sacred buildings images of the Lord, of the Blessed Virgin Mary, and of the Saints, in accordance with most ancient tradition of the Church, should be displayed for veneration by the faithful[Cf. Rite of Dedication of a Church, chapter IV, no. 10; Book of Blessings 984-1031] and should be so arranged so as to lead the faithful toward the mysteries of faith celebrated there. Care should, therefore, be taken that their number not be increased indiscriminately, and moreover that they be arranged in proper order so as not to draw the attention of the faithful to themselves and away from the celebration itself.[Sacrosanctum Concilium 125] There should usually be only one image of any given Saint. Generally speaking, in the ornamentation and arrangement of a church, as far as images are concerned, provision should be made for the devotion of the entire community as well as for the beauty and dignity of the images.
What do you think of this principle of moderation? Of pointing to the Eucharist and sacraments? Need a number be attached to it? What of multiple depictions in different media: glass, statuary, and opaque image? Does anybody really monitor this?