Pixel art is created with a limited color palette, which greatly affects the overall visual quality. It is difficult to pick out a limited number of colors, which define the color palette of an image, from a given image with hundreds of thousands of colors. We propose an automatic system, which adopts some guidelines a pixel art artist will apply, to effectively synthesize the color palette of a pixel art from a given image. Based on our approach, both artists and novices can easily attain a low-resolution image which is very close to a final pixel art. The user can then refine it to a satisfied final pixel art according to their perspective. Furthermore, we propose a palette transform for constructing a LEGO pixel art from a given pixel art while keeping the contrasts and colors as close as possible to the original pixel art provided.