1. An image processing apparatus comprising: an image generating unit configured to generate a sample texture image by extracting a texture component from a transform target image; a searching unit configured to search a preset search range for similar pixels and to generate a texture image which is greater than the sample texture image by assigning a pixel value of each of the similar pixels to a pixel value of a processing target pixel in the texture image, the preset search range being included in the sample texture image and including a first position corresponding to a second position of the processing target pixel to which any pixel value is not yet assigned, the similar pixels having, around the similar pixels, pixel value variation patterns similar to a pixel value pattern of pixels which are located in the texture image near the processing target pixel and to which pixel values are already assigned; and a combining unit configured to combine the texture image and a base image of a same size as the texture image to obtain a synthetic image, the base image holding shades similar to shades of the transform target image.