When trimming is performed on a photograph image obtained by a photography apparatus, a plurality of trimming range candidates is set by analyzing the photograph image. A judgment is made as to whether the zoom magnification ratio of the photography apparatus during photography corresponds to a predetermined limit, the limit being a maximum zoom magnification ratio or a minimum zoom magnification ratio that can be set by the photography apparatus. A trimming range is set by selecting one of the plurality of trimming range candidates. If the zoom magnification ratio is judged to be a magnification ratio corresponding to the predetermined limit, a trimming range candidate that has a smaller or larger range than that of a trimming range candidate selected if the zoom magnification ratio is judged to be a magnification ratio that does not correspond to the predetermined limit is selected as the trimming range.