An electronic device includes a lens part that receives light from a subject, an image sensor that receives the light of the lens part from a group of pixels arranged two-dimensionally, and an processor that processes an image signal of the image sensor. The image sensor performs a read-out operation at a speed to prevent blurring of an image. The processor temporarily stores image data by the read-out operation in a memory, loads a plurality of images stored in the memory to generate an image, of which the number of bits is expanded compared with the image signal of the image sensor, and performs gamma processing on the image, of which the number of bits is expanded, to generate an image compressed to the same number of bits as the image signal of the image sensor.