1. A breast x-ray imaging method comprising: x-ray imaging a first pattern of markers on or in a compression paddle and a patient's breast immobilized between the paddle and an x-ray imaging receptor to form a composite x-ray image in which both markers of the first pattern of markers and the breast are imaged; computer-processing the x-ray image to derive geometric information regarding markers of the first pattern of markers imaged in said composite x-ray image; computer-processing the geometric information to derive thickness information related to a thickness of the immobilized breast; and using the thickness information for at least one of assessment of the imaged breast and further x-ray imaging of the breast.