1. A method of measuring an object in a captured image, the method comprising: receiving a captured image from a photographing apparatus; selecting a predetermined region on the received image based on a user input; magnifying an image with respect to the selected predetermined region; obtaining brightness information of the received image; displaying at least one of the magnified image and the obtained brightness information; and selecting the object on the magnified image based on the obtained brightness information, wherein the brightness information includes brightness histograms representing a brightness distribution according to a plurality of axes on the captured image, and wherein in the displaying of the at least one of the magnified image and the obtained brightness information, as a cursor on the magnified image moves, brightness histograms with respect to a plurality of axes including the cursor are displayed.