1. An image processing apparatus comprising: an obtaining unit that obtains a user-specified display size of a preview image; a determination unit that determines an attribute of an object included in a job; an analysis unit that analyzes the object while switching the degree of analysis precision, based on the display size obtained by the obtaining unit and the attribute of the object determined by the determination unit; and a preview image generation unit that generates preview image data regarding the job, based on analysis results analyzed by the analysis unit.