The question of what it means to be “made in the image of God” is an interesting one that has been debated for quite some time. Some people think this has something to do with our physical form, or perhaps our intellect, etc. However, I think it goes back to what the word “image” means. The Hebrew word for image seems to imply the reflection of a shadow, or perhaps even an engraved statue. The phrase is uttered in the context of God blessing man with dominion over the earth.
“Then God said, ‘Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth.’ So God created man in his own image, in the image of God he created him; male and female he created them…”
He then blesses them and commands them to be fruitful and multiply and repeats his blessing that man should have dominion over the earth.
In this sense, it seems that man was created with the expressed intent that man should “image God” to creation, or represent God perhaps. We were given authority and responsibility as stewards and caretakers to demonstrate God’s glory to creation. This seems to be what the author has in mind when he says that we were made in the image of God.
However, in the fall, we ceased to image God to creation, causing even creation to fall into corruption and disobedience (reference Romans 8:18-25). After the fall, we see that when giving the genealogies that Seth seems to be created not in the image of God, but in the image of Adam (Genesis 5:3), which seems to be a fundamental shift in our nature from our origin.
Thanks be to God though that we have a Savior that has redeemed us from sin, and will restore all things back to God’s intended created order through his body and blood, which he shed for us.