An image-forming system includes an image-forming unit that forms an image of a print job on a sheet having a trimming region based on an image-forming condition; and a processor. The image of the print job includes first and second user images. The processor controls the image-forming unit to form a pattern for adjustment in the trimming region, obtains read image data related to the pattern for adjustment formed on the sheet, and adjusts the image-forming condition based on the read image data. The processor controls a display to display a print preview that represents: the first user image in a print region of the sheet that is different from the trimming region, the second user image in the trimming region, and the pattern for adjustment in the trimming region.