A method of smoothing a triangulated raster image includes the steps of: triangulating the image to create triangles having vertices, each of which is centered on a pixel of the image; comparing the costs of a first and a second orientation of an edge of each pair of adjacent triangles that forms a quadrilateral; swapping the edge of the pair of triangles to the lower cost orientation; and iterating the comparing and swapping until a stopping point is reached. The cost function used may include a cost factor that causes a triangle edge orientation that aligns with a both a color and an intensity of a color intensity contour line of the image to have a lower cost than a triangle edge orientation that does not so align.