Working through a stimulating discussion of the imago dei in Karl Barth’s Church Dogmatics, III/1.
Barth takes a decidedly different approach to what the image of God in man is from the tradition. In fact, it seems a good deal of his influence is Dietrich Bonhoeffer rather than the Reformed confessions or even broadly Protestant dogmatic tradition. Whereas the tradition taught that the image consisted of original righteousness, holiness, and knowledge, Barth emphasizes the idea of relation in act.
The first principle to keep in mind, then, in understanding Barth’s doctrine of the image is that it is articulated in a thoroughly anti-metaphysical context. What does that mean? It means that Barth stands in the tradition of modern German protestant theology which grew increasingly suspicious of speculative medieval and Greek ontological formulations. This goes back to Schleiermacher and is a common concern through Ritschl and von Harnack. So, to put it simply, the image is NOT a substance or thing which man possesses. But if it is not a substance, a thing, then what is it?
That brings us to the second principle found in Barth’s doctrine of the image. The image is fundamentally a relationship. There is an I/Thou relationship in God. However, that relationship is not that of two individuals, but of one. In God there is contained in a whole the object-subject relationship. But this I/Thou relation in God has an analogue in man, who is himself relational.
That brings us to the third principle. Man images God by virtue of his male/female relation. Man confronts man in the male/female relationship. This is the I/Thou relationship which imitates God who is himself an I/Thou, object/subject, relationship. Barth makes much of this. This IS the image of God in man. Man is the imago dei only and in so much as he is male and female.
And, finally, the image of God is Jesus Christ. Jesus Christ is himself the I/Thou relationship. He IS the male/female relation in that he is never an abstract person. But is always an everywhere the groom of his bride, the community of faith. He is the I-groom in eternal relation with his Thou-bride. He is the the solution to the age-old subject/object relation. He IS the eternal divine I who eternally relates with the human Thou in the everlasting knowledge of God as the one who is with us in a third time of redemption.
Makes, sense, right? Um, er, or does it? You decide!

I appeal to you, brothers, to watch out for those who cause divisions and create obstacles contrary to the doctrine that you have been taught; avoid them. For such persons do not serve our Lord Christ, but their own appetites, and by smooth talk and flattery they deceive the hearts of the naïve. (Romans 16:17-18)