The notion that man has the image of God is the very foundation of all Christian ethics. The notions of moral guilt, moral innocence, justice, and how one ought to treat or care for another human being are tied into the Christian world view of man bearing the image of God. Some of us haven't thought about that too much and, consequently, our ethics are anemic, and our treatment of other human beings suffers as a result. We need to have a robust understanding of this because if we allowed this notion to influence our conduct, it would radically change how we treat other human beings. It ought to teach us that we don't treat human beings as merely means to other ends, but as ends in themselves.
Human beings are valuable in themselves.
They aren't valuable because they can live a satisfying life, or because they can be healthy, or because they can make a contribution to society. They're valuable because of the kind of beings that they are innately. In abortion we're taking the life of a young, defenseless human being who is made in the image of God. We're destroying them because of some other factor. Either they are awkward, or they are in the way, or they are inconvenient, or they are painful.