1. An image processing apparatus comprising: a display unit configured to display a preview image in a first display size and in a second display size, the preview image displayed in the first display size being enlarged compared with the preview image displayed in the second display size; a storage unit configured to store image data including a first object which has a first attribute and a second object which has a second attribute being different from the first object; an analysis unit configured to, in a case that the preview image including the first object and the second object is displayed in the first display size, analyze the first object and the second object with a first analysis precision to generate preview image data for displaying the preview image in the first display size, and in a case that the preview image including the first object and the second object is displayed in the second display size, analyze the first object with the first analysis precision and the second object with a second analysis precision to generate preview image data for displaying the preview image in the second display size, a degree of the second analysis precision being lower than a degree of the first analysis precision; and a display control unit configured to control the display unit to display the preview image based on the preview image data generated by the analysis unit.