Objection 1. It would seem that the image of God is not found in every man. For the Apostle says that "man is the image of God, but woman is the image [Vulg. glory] of man" (1 Corinthians 11:7). Therefore, as woman is an individual of the human species, it is clear that every individual is not an image of God.
Objection 2. Further, the Apostle says (Romans 8:29): "Whom God foreknew, He also predestined to be made conformable to the image of His Son." But all men are not predestined. Therefore all men have not the conformity of image.
Objection 3. Further, likeness belongs to the nature of the image, as above explained (1). But by sin man becomes unlike God. Therefore he loses the image of God.
On the contrary, It is written (Psalm 38:7): "Surely man passeth as an image."
I answer that, Since man is said to be the image of God by reason of his intellectual nature, he is the most perfectly like God according to that in which he can best imitate God in his intellectual nature. Now the intellectual nature imitates God chiefly in this, that God understands and loves Himself. Wherefore we see that the image of God is in man in three ways.
First, inasmuch as man possesses a natural aptitude for understanding and loving God; and this aptitude consists in the very nature of the mind, which is common to all men.
Secondly, inasmuch as man actually and habitually knows and loves God, though imperfectly; and this image consists in the conformity of grace.
Thirdly, inasmuch as man knows and loves God perfectly; and this image consists in the likeness of glory. Wherefore on the words, "The light of Thy countenance, O Lord, is signed upon us" (Psalm 4:7), the gloss distinguishes a threefold image of "creation," of "re-creation," and of "likeness." The first is found in all men, the second only in the just, the third only in the blessed.
Reply to Objection 1. The image of God, in its principal signification, namely the intellectual nature, is found both in man and in woman. Hence after the words, "To the image of God He created him," it is added, "Male and female He created them" (Genesis 1:27). Moreover it is said "them" in the plural, as Augustine (Gen. ad lit. iii, 22) remarks, lest it should be thought that both sexes were united in one individual. But in a secondary sense the image of God is found in man, and not in woman: for man is the beginning and end of woman; as God is the beginning and end of every creature. So when the Apostle had said that "man is the image and glory of God, but woman is the glory of man," he adds his reason for saying this: "For man is not of woman, but woman of man; and man was not created for woman, but woman for man."
Reply to Objections 2 and 3. These reasons refer to the image consisting in the conformity of grace and glory.
Source: Summa Theologica (New Advent)