A radiation imaging system including an X-ray sensor with a plurality of sensor chips disposed next to each other and an image processing apparatus which performs abnormality determination concerning a white image obtained by irradiating the X-ray sensor with X-rays without any object disposed between the X-ray sensor and an X-ray generator, the system includes: an area acquisition unit configured to acquire information of partial areas of the white image which respectively correspond to the plurality of sensor chips a distribution acquisition unit configured to acquire distribution information representing variation in pixel value for each of the acquired partial areas and a determination unit configured to determine, based on the distribution information, whether abnormality is included in the white image.
