Gen 1:26 Then God said,
“Let Us make man in Our image, after Our likeness, to rule over the fish of the sea and the birds of the air, over the livestock, and over all the earth itself and every creature that crawls upon it.” 27
So God created man in His own image; in the image of God He created him; male and female He created them. 28God blessed them and said to them, “Be fruitful and multiply, and fill the earth and subdue it; rule over the fish of the sea and the birds of the air and every creature that crawls upon the earth.”
These verses are not about trinity. God was not literally talking to someone, He was not putting forward a proposal to another person. This is just an understanding within the authorities of God written down for your benefit. How is it trinity if one person proposes something to another as if they are not aware then the other person can not be God because they are not aware.
God is talking about authority here, the image is all about authority. Man is in the image of God because he is to rule over the world, something that satan stole from them and is that image that the saviour comes to redeem.
Thinking that we are created in the image of God means that we are three distinct persons in one being falls flat; are we three distinct persons in one being? of course not.
Read that verse again and especially here: "..
So God created man in His own image; in the image of God He created him; male and female He created them."