1. An image processing apparatus, comprising: a touch panel configured to output a signal for determining a center position of an orientation change operation of the image processing apparatus according to a user input, prior to a determination of a first end position of the orientation change operation; and circuitry configured to: determine the first end position based on the center position determined according to the signal, an orientation of the image processing apparatus at the first end position being different from an orientation of the image processing apparatus at which the center position is determined; control a display of an instruction instructing a user to move the image processing apparatus toward a second end position which is substantially opposite to the first end position with respect to the center position in a case where the image processing apparatus reaches the first end position, the instruction being continuously displayed until the image processing apparatus reaches the second position; determine whether the image processing apparatus has reached the second end position, after the image processing apparatus has reached the first end position; and generate a synthesized image using a plurality of images including images captured at the first end position and the second end position, after the image processing apparatus has reached the second end position, the synthesized image being wider in size than each of the plurality of images.