Sorry, here is the entire paragraph, excerpted. It says “usually” so what does that mean? Also, it seems fine to me if images are spaced in different areas, for example Divine Mercy in the Vestibule, another statue in a side-niche in church, etc. But I have heard of this “one only” rule before, in the context of trads making fun of it on other blogs.
"Thus, images of the Lord, the Blessed Virgin Mary, and the Saints, in accordance with the Church’s most ancient tradition, should be displayed for veneration by the faithful in sacred buildings133 and should be arranged so as to usher the faithful toward the mysteries of faith celebrated there. For this reason, care should be taken that their number not be increased indiscriminately, and that they be arranged in proper order so as not to distract the faithful’s attention from the celebration itself.134 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. ?