An X-ray apparatus (100, 100', 100", 200) for controlling a position of an X-ray emitter (120, 220), the X-ray apparatus (100, 100', 100", 200) comprising: - an X-ray emitter (120, 220) configured to generate X-rays and radiate X-rays to an object (10, 10a, 10b); - an X-ray detector (130, 230) configured to detect X-rays transmitted through the object (10, 10a, 10b); - a camera configured to obtain an image of the object (10, 10a, 10b) by photographing the object (10, 10a, 10b), wherein the captured image is different from an X-ray image obtained by X-ray imaging the object (10, 10a, 10b); characterised in that it further comprises: - a controller (113, 150, 250, 350) including an image processor configured to identify a candidate region of the object (10, 10a, 10b) and a central point of the object (10, 10a, 10b) by performing image processing on the obtained image, the controller (113, 150, 250, 350) being configured to: - calculate a plurality of irradiation region shapes of the X-ray emitter (120, 220) and positions of the X-ray emitter (120, 220) by matching the identified candidate region of the object (10, 10a, 10b) and the central point of the object (10, 10a, 10b) with a plurality of irradiation regions of the X-ray emitter (120, 220) and a plurality of central points of the X-ray emitter (120, 220) corresponding to different positions of the X-ray emitter (120, 220), respectively, the candidate region being a region of the object (10, 10a, 10b) to be X-rayed; and - generate a plurality of thumbnail images wherein each of the calculated irradiation region shapes and each of the calculated central points of the X-ray emitter (120, 220) to overlaps with the obtained image; wherein the X-ray apparatus (100, 100', 100", 200) further comprises: - a display (111, 141, 162, 271) configured to display the plurality of thumbnail images; - a user input receiver (112, 142) configured to receive a user input that selects one among the plurality of thumbnail images displayed on the display (111, 141, 162, 271); and - a driver configured to adjust an irradiation region of the X-ray emitter (120, 220) and a position of the X-ray emitter (120, 220) based on the user input. - an X-ray emitter (120, 220) configured to generate X-rays and radiate X-rays to an object (10, 10a, 10b); - an X-ray detector (130, 230) configured to detect X-rays transmitted through the object (10, 10a, 10b); - a camera configured to obtain an image of the object (10, 10a, 10b) by photographing the object (10, 10a, 10b), wherein the captured image is different from an X-ray image obtained by X-ray imaging the object (10, 10a, 10b); - a controller (113, 150, 250, 350) including an image processor configured to identify a candidate region of the object (10, 10a, 10b) and a central point of the object (10, 10a, 10b) by performing image processing on the obtained image, the controller (113, 150, 250, 350) being configured to: - calculate a plurality of irradiation region shapes of the X-ray emitter (120, 220) and positions of the X-ray emitter (120, 220) by matching the identified candidate region of the object (10, 10a, 10b) and the central point of the object (10, 10a, 10b) with a plurality of irradiation regions of the X-ray emitter (120, 220) and a plurality of central points of the X-ray emitter (120, 220) corresponding to different positions of the X-ray emitter (120, 220), respectively, the candidate region being a region of the object (10, 10a, 10b) to be X-rayed; and - generate a plurality of thumbnail images wherein each of the calculated irradiation region shapes and each of the calculated central points of the X-ray emitter (120, 220) to overlaps with the obtained image; - a display (111, 141, 162, 271) configured to display the plurality of thumbnail images; - a user input receiver (112, 142) configured to receive a user input that selects one among the plurality of thumbnail images displayed on the display (111, 141, 162, 271); and - a driver configured to adjust an irradiation region of the X-ray emitter (120, 220) and a position of the X-ray emitter (120, 220) based on the user input.