In a digital image matching method, reference calibration data associated with one or more reference digital image files is ascertained. The reference digital image files each have reference calibration data that is hidden metadata and can also have public metadata that is readable by a different procedure. A test digital image file is obtained and a data structure capable of holding the reference calibration data is detected in the test digital image file. The presence of second calibration data within the data structure of the test digital image file is determined. If the reference and second calibration data match, then the test digital image file and reference digital image files are from the same digital acquisition device.