1. A radiographic imaging system comprising: an imaging apparatus which irradiates radiation from a radiation source onto a subject, takes a radiographic image of said subject by detecting radiation that penetrated said subject by means of a radiation detector, and outputs image data of said radiographic image; an image processing apparatus which performs image processing of at least one of an exposure field recognition process and a trimming process on the image data of the radiographic image taken by said imaging apparatus; an image processing information storage apparatus which stores the imaging conditions of said radiographic image and image processing information which indicates the image processing performed by said image processing apparatus and its applicable range in an associated manner; and an image processing information search apparatus which searches for image processing information associated with imaging conditions of past imaging that match the imaging conditions of the current imaging, among the image processing information of the past imaging stored in said image processing information storage apparatus; wherein: said imaging apparatus changes the range of radiation exposure irradiated from said radiation source in accordance with the applicable range of the image processing of the past imaging contained in the image processing information retrieved by said image processing information search apparatus.