'Our' image? I never noticed that one before. Does god ever decree it's the only god? Or one among many?
I'm going to guess that God was speaking with his family.
[6:1] When people began to multiply on the face of the ground, and daughters were born to them,
[6:2] the sons of God saw that they were fair; and they took wives for themselves of all that they chose.
[6:3] Then the LORD said, "My spirit shall not abide in mortals forever, for they are flesh; their days shall be one hundred twenty years."
C'mon Norse and Greek god battle royale! It'd be like Avengers versus Justice League. Like Terry Cruz versus Dwayne Johnson!
[6:4] The Nephilim were on the earth in those days - and also afterward - when the sons of God went in to the daughters of humans, who bore children to them. These were the heroes that were of old, warriors of renown.