1. An image processing apparatus comprising: a first detection unit configured to detect, as an irregularity area, an area where development processing is irregular in imaging data; a second detection unit configured to detect, as approximate areas, at least two areas having approximate feature amounts in the imaging data; and a specific unit configured to specify an altered region in the imaging data from the approximate areas based on the irregularity area and the approximate areas, wherein at least one of the first detection unit, the second detection unit, or the specific unit is implemented using a processor.