1. A method of resizing an image using a resizing ratio, comprising: receiving DCT (Discrete Cosine Transform) coefficients of an input image; calculating a transformation matrix for transforming the input image using an integer aspect ratio closest to the target resizing ratio; performing a coarse resizing on the input image in a DCT domain using the transformation matrix; obtaining a spatial image by performing an IDCT (Inverse Discrete Cosine transform) on the coarse-resized domain; and forming an output image by performing a fine resizing on the spatial image in a spatial domain.