1. An image processing apparatus that performs a type of image processing selected from a plurality of types of image processing, on an image, comprising: a display device that displays the image; a designating device that designates a starting point and an ending point on the displayed image; a first acquiring device that acquires information on the starting point and the ending point; a selecting device that displays the plurality of types of image processing in an area set at a location based on the designated ending point on the displayed image and selects a type of image processing to be performed based on a user instruction; a second acquiring device that acquires information on the selected type of image processing; a defining device that defines a processing area of the displayed image, in which the selected type of image processing is to be performed, according to the acquired information on the starting point and the ending point and the acquired information on the selected type of image processing, wherein a plurality of shapes for the processing area are set in advance according to the plurality of types of image processing, and said defining device sets the shape of the processing area to one of the plurality of shapes in accordance with the acquired information on the selected type of image processing; and a display changing device that changes display of the image in the defined processing area.