In chapter 1, Maimonides begins with a discussion of the phrase “Let us make man in our image” from Genesis 1:26, and writes about how the use of the word “image” (Arabic: صورة ; Hebrew: צלם) misleads people into thinking that the Bible describes a corporeal God. In other words, a literal reading of the Torah seems to suggest that God has a body with a face and limbs.

Maimonides is at pains to explain that this literal reading is wrong, not least because it denies the greatness of God. It is in this chapter that he sets out his tripartite skeleton for a theology that is consistent with the Law: that God exists, that he is One, and that he is Incorporeal. In fact, he insists, “there is no real unity without incorporeality”.

The words of the Bible must mean, of course, that man is “similar” to God for some meaning of the word “similar” (with apologies to the author for using a word he would undoubtedly have disapproved of). For Maimonides, the way in which man has been created “in God’s image” is by virtue of his ability to intellect (“إدراك الإنساني” or “إدراك العقلي”). This is what sets man apart from all other living things, and also accounts for why God said “نَعْمَلُ الانْسَانَ عَلَى صُورَتِنَا كَشَبَهِنَا” in Genesis 1.26.

It is interesting to compare Maimonides’ perspective on what “image” means with others.

Radak:

Basically, whether we speak of “the image of G’d,” or of “an angel,” the common denominator is that we speak of disembodied spiritual beings. G’d is distinguished by the fact that none of the other disembodied intelligent beings (angels) amounts to anything at all, seeing none of them can understand their Creator’s essence. This is an axiom, seeing that G’d is the ultimate cause of their existence. He is the Creator, whereas they are merely creatures. This is why Moses added the word אלוקים, when mentioning צלם, to make sure that we get the point that if man is compared to something celestial, he is compared to a creature in the celestial regions, not to the Creator himself.

Rav Kook, writing in For the Perplexed of the Generation:

The foundation of the Torah is that man was created “in the image of God”. The essential meaning of “the image” is the complete freedom we find in man, [which means] that man must have free will.