According to an embodiment, an image output device includes an extractor, a search unit, an associate unit, and a controller. The extractor is configured to extract a first parameter that varies in accordance with a movement of an object from at least one first image of the object, and extract a second parameter that varies in accordance with a movement of the object from each second image of the object. The search unit is configured to search for a second parameter similar to the first parameter. The associate unit is configured to associate the first image from which the first parameter is extracted with the second image from which the second parameter that is retrieved with respect to the first parameter is extracted. The controller is configured to instruct an output unit to output an image based on the first and second images that are associated to each other.