'An image' or 'images' signify falsities from self-derived intelligence.

(References: Apocalypse Explained 304)

585. The openings or gates to the hells that are beneath the plains and valleys present to the sight different appearances. Some resemble those that are beneath the mountains, hills and rocks; some resemble dens and caverns, some great chasms and whirlpools; some resemble bogs, and some standing water. They are all covered, and are opened only when evil spirits from the world of spirits are cast in; and when they are opened there bursts forth from them either something like the fire and smoke that is seen in the air from burning buildings, or like a flame without smoke, or like soot such as comes from a burning chimney, or like a mist and thick cloud. I have heard that the infernal spirits neither see nor feel these things, because when they are in them they are as in their own atmosphere, and thus in the delight of their life; and this for the reason that these things correspond to the evils and falsities in which they are, fire corresponding to hatred and revenge, smoke and soot to the falsities therefrom, flame to the evils of the love of self, and a mist or thick cloud to falsities from that love.