On receipt of a request related to picture display from a user terminal, a central device transmits an instruction to the plurality of distribution devices and to the plurality of receiving devices, according to a usage condition of the transmission line and {HEAD ~ the number} of {TAIL ~ simultaneously distributed pictures} 
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On receipt of a request related to picture display from a user terminal , a central device transmits an instruction to the plurality of distribution devices and to the plurality of receiving devices , according to a usage condition of the transmission line and { HEAD ~ the number } of { TAIL ~ simultaneously distributed pictures }
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