An image processing apparatus includes: a reference object discriminating unit that discriminates a reference object from a digital image that is taken by capturing an object together with the reference object; a size information extracting unit that extracts size information of the reference object in the digital image; a size information comparing unit that acquires target size information of the reference object, and compares the size information of the reference object that is extracted by the size information extracting unit with the target size information; a correction size amount setting unit that sets a correction size amount on the basis of the comparison result of the size information comparing unit; and an image processing unit that performs image processing on the digital image in accordance with the correction size amount that is set by the correction size amount setting unit.