An image forming system includes an image forming apparatus and a mobile terminal. The image forming apparatus forms an image on paper. The image forming apparatus includes a controller that generates data of a temporally changing image that represents a temporal change of the image. The mobile terminal includes an imaging section, an operation display section, a transmitter-receiver, and a controller. The imaging section generates data of a captured image by capturing the image formed on the paper. The operation display section displays the captured image. The transmitter-receiver is connected to the controller via a network. The controller controls the transmitter-receiver to obtain the data of the temporally changing image from the controller. The controller controls the operation display section to display the temporally changing image over the captured image.