Provided is an information processing system, including a processor, a storage device and a display device. The storage device stores images captured by imaging devices. If an image of a moving object is selected as a search query, then the processor executes a similarity search on the images stored in the storage device, with the selected image as the search query. The display device displays images attained as results of the similarity search. If an image of a moving object is added as a search query, then the processor executes a similarity search with all selected images as search queries. The display device updates images to be displayed such that images attained as results of the similarity search performed with all the selected images as the search queries are displayed.