Disclosed herein is an apparatus and method for processing a digital image, where analog images are converted to digital images and stored. The method for processing a digital image includes sensing a first hand-drawn sketch and storing the sensed first hand-drawn sketch as a first digital image; visualizing the stored loaded first digital image as a first virtual hand-drawn sketch; sensing a second hand-drawn sketch being additionally drawn on the visualized first virtual hand-drawn sketch; and storing the sensed second hand-drawn sketch as a second digital image, wherein the first hand-drawn sketch and the second hand-drawn sketch corresponds to a physical sketch being expressed with a liquid or solid substance hand-drawn by a user.