1. God is a spirit, so his image would be a spirit.
No, GOD is infinite spirit, invisible.... and the point is that the image is the visible revelation of the invisible GOD.
The 'image' is tangeable, visible, the knowable expression of the very essence of GOD.
G5481
image-χαρακτήρ
charaktḗr; gen. charaktḗros, masc. noun from charássō (n.f., see cháragma [G5480]), to carve. Occurs only in Heb_1:3 where it is translated "express image," referring to Jesus Christ. Here He is described as the charaktḗr tḗs hupostáseōs autoú (tē̄́s [G3588], the [gen. fem.]; hupostáseōs [G5287], essence [gen.]; autoú [G846], he [gen. masc.]), "the exact image of His [God's] essence" (a.t.). Whatever the divine essence is, Jesus is said to be its perfect expression. The writer of Hebrews thus sets forth a high Christology affirming the deity of Jesus Christ.-Spiros Zodhiates "Complete Word Study Dictionary"
The term 'firstborn' naturally means the first one born, but was modified in GOD's election to be a title of rank.
Of Noah's sons, Japheth was the first born, but Shem is mentioned first because he carries the blessing and inheritance.
Of Abraham's sons, Ishmael was born first, but Isaac becomes the 'yachid/only' son.
Of Isaac's sons, Esau is born first, but Jacob gets the blessing and inheritance.
Of Jacob's sons, Reuben is born first, but the King will come from Judah.
Of Joseph's sons, Manassah is born first, but GOD calls Ephraim His firstborn.
In Psalms, the prophesy describes the future Messiah as GOD's firstborn by election.
The LORD Jesus Christ is the firstborn from the dead and the firstborn of the new creation. This has nothing to do with His beginning in time. HE exists eternally.
Whatever GOD's 'substance' is, Jesus Christ is the same 'substance'.
Deity has no beginning and is uncreated.
Heb 1:3 who being the effulgence of his glory, and the very image of his substance
Do you really not understand, that before the creation there was nothing but that which is uncreated and has no beginning.....GOD.
This Spirit is GOD!