An image was a two-dimensional or three-dimensional representation of an individual or a thing.
In the 2260s, the bridge viewscreen of the Constitution-class starships created images of what was outside the ship. (TOS: "The Corbomite Maneuver")
In 2254, when he was reliving his memory of the mission to Rigel VII, Captain Christopher Pike saw Vina near the deserted fortress. Although she had longer hair and a different dress, he recognized her as the one the illusory survivors of the crashed SS Columbia called Vina. He was not sure she was real, wondering if this was an image of a girl named Vina created by the Talosians. (TOS: "The Cage")
In 2265, Gary Mitchell saw the image of the starboard impulse packs, with the points almost decayed to lead, in Lee Kelso's mind. (TOS: "Where No Man Has Gone Before")
In 2364, while under the effects of polywater intoxication, Tasha Yar went to Counselor Deanna Troi's crew quarters for advice on clothes, as Troi always wore such beautiful clothes while off duty, and Yar wanted to change her image. (TNG: "The Naked Now")
That same year, Lutan sent a transmission from the planet surface of Ligon II to the USS Enterprise-D and requested Captain Jean-Luc Picard's image to be displayed, but Picard required an image of the kidnapped Tasha Yar. (TNG: "Code of Honor")