Angels have free will: at any time unless they sin...
Angels worship GOD:
Hebrews 1:6 points out that angels worship the Lord. We also see the heavenly host praising God in Luke 2:13–14. Robotic praise and worship is a parody of the real thing and worthless in heaven.When you put on a dvd and listen to a worship song singing praises to GOD, do you think or allude to the dvd as worshipping? Of course you don't.
Some angels are elect:
1 Timothy 5:21 - I charge thee before GOD and the Lord Jesus Christ, and the elect angels. implying the fallen angels are demons and the people of the evil one, the tares, sown into the world by the devil. IF angels can choose to sin and become demons, they can also choose to be holy and work for GOD.
Angels are holy:
Mark 8:38 If anyone is ashamed of me and my words in this adulterous and sinful generation, the Son of Man will be ashamed of him when he comes in his Father's glory with the holy angels. This verse contrasts the of evil of men with the holiness, that is, the righteousness of angels, not just their consecration to GOD. Robotic holiness is a farce...a stone cannot sin but it is not righteous and a robot neither can be holy, that is, in the context of this verse, righteous. As well, Satan's fall is proof of his free will as he is not guilty of anything if he is a robot...
Angels have emotions such as love, joy, desire, sadness, pride, and anger:
Luke 15:10 indicates that angels are joyous when one person repents. The devil has great wrath in Revelation 12:12. The angels and the devil have desires (1 Peter 1:12; John 8:44). Why would anyone create a robotic group with emotions to drive them when HIS will is all that is necessary to drive them? Robotic emotions??? Surely only people have emotions...
Angels are Persons in the image of GOD:
In the resurrection, man will be as the angels of God.
Matt 22:30 For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven. In the resurrection, man is restored to the image of God in which he was created. The angels of God must, therefore, bear the image of God.
The image of GOD cannot contain sin therefore for man to be a sinner, the image must be broken. In the resurrection we will be restored to the full image of GOD and like the angels as this verse hints, who therefore must also be in HIS image.
When did they receive the image of God unless it was in creation?
The image of GOD? I think it means things like personhood that is, self awareness, intelligence, emotional ability, curiosity and creativity and the ability to make true free will decisions. Emotions are further proof of their personhood in the image of GOD. Therefore any being that fits this description fits the image of GOD...
Not only does the ability to worship, to praise, to be elect and to be holy imply personhood, they also imply they have free will and if you combine free will with election of some and the fall of others, you get angels going through an Adam like choice with some staying holy and satan and his crew choosing that which made them evil in HIS sight.
My concept is that all people created in HIS image were created as ingenuous innocent with the potential, ability and opportunity to choose to become perfectly good/holy or perfectly /eternally evil and we had to choose to accept GOD and HIS life for us in heaven to fulfill our potential to be perfectly good. Our fall into sin delayed the fulfillment of that potential by making it impossible to fulfill without grace. Our redemption is a restoration to the potential and the sanctified new creation is the fully realized fulfillment of HIS purpose for our creation in us.