1. A method of operating an electronic device, comprising: displaying, by a display unit of the electronic device, an image as a preview; differentiating, by a control unit of the electronic device, a reference object and a wearable device in the image; determining, by the control unit, a reference color of the reference object and a background color displayed by the wearable device; adjusting, by the control unit, the background color of the wearable device so as to correspond to the reference color of the reference object; and setting, by the control unit, the background color of the wearable device.