1. A camera-based mobile communication device, comprising: a light sensor operable to detect a brightness value of an external light source; a camera module operable to capture an image; a flashlight operable to generate a flash; and a micro-processing unit (MPU) electrically connected to the light sensor, the camera module, and the flashlight, wherein the MPU comprises: a comparison module operable to compare the brightness value with a threshold brightness value; and a face recognizing module operable to determine whether there exists a facial feature in the image; and a flashlight control module operable to turn on the flashlight when the comparison module determines that the brightness value is greater than the threshold brightness value and the face recognizing module recognizes the facial feature from the image.