1. A method comprising: detecting one or more face images from at least one photographic image; selecting a face image having a pose orientation that substantially matches an original pose orientation of a character in a cartoon image; replacing a face of the character in the cartoon image with the face image; and blending the face image with a remainder of the character in the cartoon image by operations including: converting, by one or more processors, the face image into a color space that includes an illumination channel and a plurality of color channels; performing a shading on the illumination channel of the face image based at least in part on illumination information of the cartoon image, the shading including one or more uniform color regions and an illumination value for each region; performing an illumination blending after the face image replaces the face of the character in the cartoon image by keeping illumination smooth across the regions; and performing color adjustment on the plurality of color channels in the color space.