1. An image arrangement apparatus comprising: an association unit configured to associate, for a plurality of images represented by image data, image data with an arrangement reference point through an image reference point of the image data, wherein a number of arrangement reference points disposed in a collage region is equal to or more than the number of images to be arranged in the collage region; a setting unit configured to set, in the collage region and for each image data, an image reference point arrangement region based on a size of the image represented by the image data associated with the arrangement reference point and based on a position of the arrangement reference point associated with the image reference point of the image data; a generation unit configured to generate a collage image of the plurality images for display on a display unit, wherein, for each of the plurality of images, the generation unit positions an image reference point of the image data within the image reference point arrangement region associated with the image data to arrange each image of the plurality of images in the collage region; and at least one processor, wherein the at least one processor implements the association unit, the setting unit, and the generation unit.