A hand-held device for recording three-dimensional holographic images, taken up as a hobby by Voyager's Doctor, whose old pictures lead him to a buried memory in Latent Image.
The holo-imager is the Federation's descendant of the camera, capturing a subject as a small holographic image that can be viewed from any side. Voyager's Doctor becomes an enthusiastic and tireless user, to the dismay of shipmates made to sit through his slide evenings, as at the start of Nothing Human.
The device drives the plot of Latent Image (2375). Making full-body portraits of the crew for their medical records, the Doctor finds traces of an operation on Harry Kim that he does not remember performing. Looking back through his older images with Seven of Nine, he finds pictures of an ensign he does not know, Ahni Jetal.
The trail leads to Captain Janeway, who had his memory of Jetal's death erased eighteen months earlier, after his choice to save Kim instead of her sent his programme into a destructive loop.