1. An image processing method for an image comprised of a plurality of pixels, wherein each pixel has an alpha value and an image data, the method comprising: selecting a first pixel and a second pixel, wherein the first pixel and the second pixel are neighboring each other; detecting the alpha value of the first pixel and the alpha value of the second pixel; determining the image data of the first pixel and the image data of the second pixel; determining interpolated pixels according to the first and second pixels; generating weighting values of interpolated pixels, wherein the weight value for each interpolated pixel are different to each other; and adjusting the image data of the interpolated pixels if one of the first and second pixels has the alpha value being zero.