Some embodiments are directed to an image processing apparatus comprising obtaining a reference image and a verification target image; selecting one or more defect detection processing from a plurality of types of defect detection processing for performing defect detection in the verification target image; executing the selected one or more defect detection processing on a difference image between the reference image and the verification target image in accordance with processing parameters of the selected one or more defect detection processing; and outputting a result display screen in which a defect in the verification target image and a defect detection processing used for detecting the defect can be identified, in a case where the defect is detected.