1. An image forming system comprising: an image forming apparatus including an image forming unit for forming an image on a sheet, an image reading unit for reading a sheet surface on which the image is formed and generating a scan image, an image inspection unit for detecting abnormalities within the scan image, and a history generating unit for generating detection information of each of the abnormalities detected by the image inspection unit and generating a history image by embedding the detection information in areas of the scan image where the abnormalities were detected by the image inspection unit; a storage device for storing the history image; and a user terminal for displaying an abnormality detection result by the image inspection unit by using the history image and inputting a user's evaluation of the abnormality detection result, wherein the image forming apparatus further includes a parameter setting unit for finally determining the abnormalities within the scan image depending on the user's evaluation input in the user terminal, and determining and setting abnormality detection parameters to be used in the image inspection unit such that the abnormalities finally determined are detected, and the abnormalities not finally determined are not detected.