Provided is a technique that enables efficient setting of poster printing and efficient processing of an image. To this end, a control apparatus of the present invention is a control apparatus that allows a printing apparatus to print multiple divided images, into which an input image is divided, on print media, including: a setting unit that sets the number of divisions of the input image based on user input; an obtaining unit that obtains a width of the print media; a determining unit that determines a scale factor of the input image based on at least the set number of divisions, the width of the print medium, and a width of the input image; and a display control unit that displays a preview screen of the input image and a processing instruction item for instructing processing of the input image together, in which in a case where processing of the input image is instructed by user operation through the processing instruction item, the display control unit displays a processed input image reflecting the processing based on the processing instruction, and the determining unit determines a scale factor of the processed input image based on a width of the processed input image.