1. An image forming apparatus comprising: a display section for executing display based on image data including a plurality of images; a first image processing section for generating first images respectively corresponding to the images included in the image data, to which an image process based on information of a job is not executed; a second image processing section for generating a second image obtained by executing the image process based on the information of the job to the image data of the first image currently displayed in the display section; and a control section for causing the display section to display the first image corresponding to the image data to which the job is set and to switch the currently displayed first image to the corresponding second image after completing a generation of the second image by the second image processing section.