An information processing terminal device includes: an acquiring unit acquiring image data; a detecting unit detecting a posture of the information processing terminal device; a generating unit generating display image data based on the image data acquired in the acquiring unit according to the posture of the terminal device detected by the detecting unit; and a displaying unit displaying the display image data generated by the generating unit on a display unit. If the posture of the terminal device is changed, the generating unit generates the display image data according to the changed posture of the terminal device. If the posture of the terminal device is changed during the generation of the image data by the generating unit, the generating unit does not generate the display image data according to the changed posture of the terminal device, until the generation of the display image data is completed.