1. An electronic device comprising: a flexible display; a camera module comprising a plurality of cameras; an image processing unit; a sensor unit; and a control unit configured to: control, in response that the sensor unit detects a bending direction to be inward, the plurality of cameras to drive sequentially for capturing images of an object when the electronic device surrounds the object in a shape of a closed curve; sequentially, when the plurality of cameras drive sequentially, drive parts of a display area of the flexible display that respectively correspond to positions of the sequentially-driven cameras; and control the image processing unit to synthesize the captured images into one image and process the synthesized image into a three-dimensional (3D) image.