1. An image generation device comprising: a video image generation unit that extracts images of a target photographic subject within a photographic subject respectively from a plurality of captured images that are acquired by capturing images of the photographic subject in time series and generates a video image of the target photographic subject based on the extracted images of the target photographic subject, the target photographic subject moving in the generated video image; and a background image generation unit that generates a single still background image, in which an image of the target photographic subject is eliminated, based on the captured images, wherein: the generated video image and the generated single still background image are recorded into a recording medium respectively in mutual correspondence to each other, and by combining the generated video image on the generated single still background image recorded in the recording medium, the video image of the target photographic subject is reproduced on the single still background image so as to dynamically reproduce one of the captured images.