PROBLEM TO BE SOLVED: To enable a shorter communication time for communicating a plurality of radiation images to the outside when generating a composite radiation image composed by connecting the plurality of radiation images.SOLUTION: In a radiation image photographing system, a plurality of radiation images 15 in which overlapping regions are overlapped are acquired by a radiation detector 14. The radiation images 15 include a positioning region 17 including at least a part of the overlapping region and an area other that the positioning region 17. A control part 31 of a control apparatus 30 in a cassette 12 sets a compression rate of the positioning region 17 low and a compression rate of the region other than the positioning region 17 high, compresses image data of the radiation images 15, and transmits it to a console 20. A control part 40 of the console 20 receives the compressed image data of the radiation images 15, performs positioning. on the basis of an image data of the positioning region 17 and
