An image judging system includes a server and a mobile terminal performing communication therewith. The server includes a position calculating unit that calculates positions of an image of interest and a first landmark image corresponding thereto of a judging target image in whole image data obtained on the basis of a judging target image. The mobile terminal includes: a display unit displaying the image data and the guide mark together; and an imaging unit capturing an image of the judging target image, thereby generating image data, and generating image data related to the judging target image. The server or the mobile terminal includes a guide information generating unit calculating a position of a guide mark on the basis of a position of the detected first landmark image in the image data and a positional relationship between the image of interest and the first landmark image in the whole image data.