Trinitarian theology says that one can point to Christ on the cross and say, "That is God." Fully, truly, without qualification. The Trinity, though, is also God, so one can point to an image or symbol involving Father, Son and Holy Spirit and say, "That also is a picture/symbol/representation of God."
Genesis makes clear that the image of God in humanity benefits from this same phenomenon. Setting aside the issue of the fall and simply looking at it in the abstract, each individual human is the image of God. On top of that, "the two-become-one that multiplies" is also, in itself an image of God.
So one can look at a stick figure or a smiley face drawing and say, "That is the image of God." One can also look at a picture of a man, woman, and child and say, "That is also the image of God." Not three images of God in one picture, but one unified image of God.
Individualism rejects this other way of viewing the image of God in humanity and insists that it is always and only the unique, discreet individual who bears the image of God. The hard thing is to add the other image without somehow detracting from the individual one.