Howdy Quans,
Greetings. There have been a number of suggestions for the obvious plural.
Genesis 1:26-27 (KJV): "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. 27 So God created man in his own image, in the image of God created he him; male and female created he them."
When God speaks in v.26 there is the plural of "us", "our" and "our". But when it records Gods creation in v.27, there is in contrast a singular "his", "he and "he". A first step in understanding this is to recognize that in both verses, the word "God" (Heb. "Elohim") is a plural word, and according to the context this is translated as "God", "god", "gods", "angels", "judges".
David using terms from the creation speaks of the new creation centred in Jesus.
Psalm 8:4-8 (KJV): "4 What is man, that thou art mindful of him? and the son of man, that thou visitest him? 5 For thou hast made him a little lower than the angels, and hast crowned him with glory and honour. 6 Thou madest him to have dominion over the works of thy hands; thou hast put all things under his feet: 7 All sheep and oxen, yea, and the beasts of the field; 8 The fowl of the air, and the fish of the sea, and whatsoever passeth through the paths of the seas."
In the above KJV "the angels" is the same word "Elohim" as in Genesis 1:26,27, and if "angels" is accepted here then this confirms that the plural of Genesis 1:26-27 includes the angels.
This is not universally accepted because some translations do not translate "Elohim" here as "angels", refer the following:
Psalm 8:5 (1901 ASV): "For thou hast made him but little lower than God, And crownest him with glory and honor."
Psalm 8:5 (RSV): "Yet thou hast made him little less than God, and dost crown him with glory and honor."
In each of the above, KJV "the angels, ASV "God", RSV "God" is the same word as "God" in Genesis 1:26,27.
The KJV translation of Psalm 8:5 is confirmed to be acceptable and even preferred by the quotation and comments on Psalm 8:5 in the following:
Hebrews 2:7-9 (KJV): "7 Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands: 8 Thou hast put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him. 9 But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man."
David then interprets Genesis 1:26, telling us that the plurality includes the angels, and this is also confirmed by the writer to the Hebrews. This all shows that Genesis 1:26-27 speaks concerning the creation of man by the One God and the angels.
Kind regards
Trevor