It isn't the biggest ego trip going.
Really - let's summarise.
God creates everything and then decides to create something
in his own image, i.e. man (that's a pretty sizeable ego trip if you are man - created in the image of god). And then God tells you that you are in charge of everything else - so not only are you created in the image of God but you have dominion over everything else.
And of course if you consider that God to be actually a creation of man then the ego trip is amplified further - we created a divine entity to tell us that we are divine-like (created in his image) and also to tell us that everything else is our play-thing.
Just in case you've forgotten these are the words (KJV):
'1:26 And 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 fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
1:27 So God created man in his own image, in the image of God created he him; male and female created he them.
1:28 And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.'