The characteristic-detecting unit (20) is operable to detect characteristics from a first or second information terminal unit-captured image. The first information terminal unit-captured image has been obtained by an image input unit (10). The second information terminal unit-captured image has been decoded by an image-decoding unit (80). The characteristic-detecting unit (20) is further operable to control an image-encoding unit (30), an image-displaying unit (90), the image-decoding unit (80), or the image input unit (10) in accordance with the characteristic information. The control system provides a reduced amount of processing required for image encoding, either stops displaying the images or displays fewer images, either stops transferring the images from the image-decoding unit (80) to the image-displaying unit (90) or transfers fewer images therebetween in the same transfer direction, and provides fewer image-captured frames. This feature provides an information terminal unit characterized by thrifty power consumption.