This isn't an authoritative quote, just something I read recently:
A helpful classification of approaches to the imago Dei was provided by Noreen Herzfeld in 2002, and subsequently developed by Wentzel van Huyssteen in his Gifford Lectures. The four possibilities for interpreting the image of God in humans can be summarised as follows: substantive, based on some property distinctively possessed by human beings; functional, based on some role or vocation allotted by God to humans; relational, based on both capacity and call, to enter into loving relations with God and neighbour; and eschatological, based on the idea that humans' true nature lies ahead of them - it is a goal rather than a present reality.
-Christopher Southgate, Theology in a Suffering World: Glory and Longing, 227-8
Here is the Catholic Catechism on the question:
1702 The divine image is present in every man. It shines forth in the communion of persons, in the likeness of the unity of the divine persons among themselves (cf. chapter two).
1703 Endowed with "a spiritual and immortal" soul, the human person is "the only creature on earth that God has willed for its own sake." From his conception, he is destined for eternal beatitude.
1704 The human person participates in the light and power of the divine Spirit. By his reason, he is capable of understanding the order of things established by the Creator. By free will, he is capable of directing himself toward his true good. He finds his perfection "in seeking and loving what is true and good."
1705 By virtue of his soul and his spiritual powers of intellect and will, man is endowed with freedom, an "outstanding manifestation of the divine image."
1706 By his reason, man recognizes the voice of God which urges him "to do what is good and avoid what is evil." Everyone is obliged to follow this law, which makes itself heard in conscience and is fulfilled in the love of God and of neighbor. Living a moral life bears witness to the dignity of the person.
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Catechism of the Catholic Church, Man: The Image of God
The tradition I am familiar with is basically substantive, where the image of God is seen in such powers as rationality, freedom, the ability to love, etc. It is such things that set man apart from lower creation and allow him to know and love God.