A method of processing an image of a portable terminal, the portable terminal comprising an image signal processor (ISP) and an application processor (AP) includes: acquiring, at the ISP, an image from a camera unit of the portable terminal for each frame of a plurality of frames during an operation of the camera; generating, at the ISP, a display image and a compression image by processing the acquired image; transmitting the display image generated by the ISP for each frame and the compression image at a preset frame interval; and displaying, at the AP, the acquired display image and buffering, at the AP, the compression image.