A method for operating an x-ray image recording device having a movable x-ray detector on an-x-ray c-arm is provided. The x-ray C-arm supports an x-ray source and the x-ray detector which can be moved in the direction of the x-ray source. A variable is calculated which specifies the image quality of an x-ray image to be obtained in a position of the x-ray C-arm in a position of the x-ray detector and/or specifies the exposure dose of an operating person. A measure is taken as a function of the variable which results in a movement of the x-ray detector by the operating person and/or by an automatic movement. X-ray images are recorded in positions of the x-ray detector in which the image quality and/or the exposure dose of an operating person are optimal.