The present invention is directed to a technique for preventing accidental removal of a print product, including the case of one portion of the print product being pulled out, without keeping a user waiting for print output. An image processing system includes an output unit configured to output, to a monitoring tray, an output result of a print job to which a monitoring attribute is allocated, an imaging unit configured to capture a video of the monitoring tray, a detection unit configured to detect motion in an output product region of the monitoring tray, based on the video captured by the imaging unit, and a warning information output unit configured to output warning information in a case where the detection unit detects motion in the output product region.