Concerning the image of God and whether is can somehow be lessened in a man, there are some CCC quotes available, but to me they seem rather oriented to original sin and man as a whole. Not that this necessarily stops them from applying to a man. Also note the switch to the word “likeness” in one of the quotes.
844 In their religious behavior, however, men also display the limits and errors that disfigure the image of God in them…
705 Disfigured by sin and death, man remains “in the image of God,” in the image of the Son, but is deprived “of the glory of God,” of his “likeness.”…
1701 …It is in Christ, Redeemer and Savior, that the divine image, disfigured in man by the first sin, has been restored to its original beauty and ennobled by the grace of God.