1. An image processing apparatus comprising: one or more processors; and a memory storing instructions which, when the instructions are executed by the one or more processors, cause the image processing apparatus to function as: an obtaining unit configured to obtain an image signal that is capable of generating a plurality of reconstruction images which have mutually different focus states; a generating unit configured to generate a reconstruction image from the image signal obtained by the obtaining unit; a display control unit configured to cause a display to display a reconstruction image generated by the generation unit; a receiving unit configured to receive an instruction for performing enlarged display or reduced display; and a control unit, wherein, upon receiving an instruction for performing enlarged display or reduced display while a reconstruction image is displayed on the display, the control unit selectively causes the display control unit to perform enlarged display or reduced display of the displayed reconstruction image, or to perform enlarged display or reduced display of an other reconstruction image which is generated by the generating unit and has a different focus state from the displayed reconstruction image.