1. An image processing apparatus, comprising: an acquiring unit configured to acquire an image to be decorated; an input unit configured to input an instruction to designate a pattern of a decor for decoration to the image acquired by the acquiring unit; a determining unit configured to determine a width of the decor, according to the pattern of decor designated by the instruction input by the input unit; and a decoration unit configured to decorate the image acquired by the acquiring unit by using the pattern designated by the instruction with the width determined by the determining unit.