An image processing system includes a portable terminal and an image processing device that wirelessly communicates with the portable terminal. The portable terminal includes a first CPU that sends a connection request to the image processing device to request to establish a connection with the image processing device and that sends an execution start command to enable the image processing device to execute a job when the connection with the image processing device is established. The image processing device includes a wireless communication interface that establishes the connection with the portable terminal in response to the connection request from the portable terminal and a second CPU that receives the execution start command from the portable terminal, executes the job based on the execution start command in order of receipt, and terminates the connection with the portable terminal after the execution start command is received.