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 the scan image; a storage device (12, 202) 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, the user terminal is configured to display the scan image and abnormality detection information within the history image as the abnormality detection result, and input a user's evaluation of whether or not each of the abnormalities within the scan image is an abnormality to be detected, the user terminal is configured to delete, add, or change the abnormality detection information within the history image depending on the user's evaluation, and generate a modified history image, and the parameter setting unit is configured to finally determine the abnormalities within the scan image, based on the abnormality detection information within the modified history image. 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 the scan image; a storage device (12, 202) 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, the user terminal is configured to display the scan image and abnormality detection information within the history image as the abnormality detection result, and input a user's evaluation of whether or not each of the abnormalities within the scan image is an abnormality to be detected, the user terminal is configured to delete, add, or change the abnormality detection information within the history image depending on the user's evaluation, and generate a modified history image, and the parameter setting unit is configured to finally determine the abnormalities within the scan image, based on the abnormality detection information within the modified history image.