Answer: “The whole being… and not something in man but man himself, is the image of God.”
Explained: In Lutheran theology the image of God is restricted to original righteousness and was therefore totally lost when the latter was lost.
In this theology the lines of demarcation between the spiritual and the worldly, between the heavenly and the earthly, are so sharply drawn that the result is two hemispheres, and the connection between nature and grace, between creation and re-creation is totally denied.
The supernaturalist view is still at work here; the image of God stands alongside nature, is detached from it, and is above it. The loss of the image, which renders man totally deaf and blind in spiritual matters, still enables him in earthly matters to do much good and in a sense renders him independent from the grace of God in Christ.
Reformed theology, on the other hand, by its distinction between the image of God in a broader and a narrower sense, has most soundly maintained the connection between substance and quality, nature and grace, creation and re-creation. It must be granted that this distinction has often been conceived too mechanically and needs to be further developed organically.
Nevertheless, Reformed theology has most vividly brought out the fact that the image of God in the narrower sense is most intimately bound up with that image in the broader sense, and that the two components together make up the full image of God. The whole being, therefore, and not something in man but man himself, is the image of God.
Further, sin, which precipitated the loss of the image of God in the narrower sense and spoiled and ruined the image of God in the broader sense, has profoundly affected the whole person, so that, consequently, also the grace of God in Christ restores the whole person, and is of the greatest significance for his or her whole life and labor, also in the family, society, the state, art, science, and so forth.
Source: Herman Bavinck, Reformed Dogmatics, Volume 2, 553–54.