1. An image processing method in which a trimmed image is obtained by carrying out trimming for cutting out from a photographic image obtained by taking a photograph of an object comprising a reference part, and one or more other part which, in a state where the object is not inclined, has a common centerline with the reference part and is arranged in a direction in which the centerline of the reference part extends, an image of an area including a part or the whole of the reference part and said other part along a trimming centerline at a predetermined angle to the centerline of the reference part, wherein the improvement comprises: a processor to perform the steps of: obtaining the centerline of the reference part of the photographed object and at the same time, detecting a degree of inclination of said other part of the photographed object with respect to the centerline of the reference part and a direction of the inclination upon taking the photograph from the photographic image, determining said predetermined angle so that the trimming centerline is inclined by a larger angle away from the centerline of the reference part toward the direction of the inclination of said other part as the degree of inclination of said other part increases on the basis of the detected degree of inclination of said other part, and carrying out the trimming along a trimming centerline at the determined angle.