In Genesis 1:26-27, God said, "Let us make man in our image, after our likeness. And let them have dominion over" all the earth. "So God created man in His own image, in the image of God He created him; male and female He created them."
What does it mean to be made in the image and likeness of God? Often this is interpreted to mean that we look like God. Surely you've seen paintings of God as an old man even wearing clothes.
But Numbers 23:19 says, "God is not man," and Jesus said in John 4:24, "God is spirit." So God has no human or even physical form. Rather, to be made in the likeness of God means that we are like God, in the sense that we are relational beings as God is. We've also been given dominion as God has dominion, to fill the earth and subdue it.
Most of all, being made in the image of God means that we are to reflect His holy and righteous character. Animals cannot make moral decisions. It is for men and women to glorify God in righteousness. Every person's life is sacred because we are all fellow image-bearers of the one who made us.
When we sin, doing what is contrary to God's righteousness, we desecrate God's image. Romans 3:12 says together we have become worthless before God, good to be cast into the flames. But Jesus cleanses us from all unrighteousness, and by faith in Him, we are being remade into the image of the Son, to reflect the holy and righteous character of Christ, when we understand the text.
"Those whom He foreknew He also predestined to be conformed to the image of the Son..." Romans 8:29
"He chose us in Him before the foundation of the world, that we should be holy and blameless before Him." Ephesians 1:4