This is a commissioned portrait.
This illustration is hand made on digital tablet with an optical stylus and it is a vector image.
Vector graphics are computer graphics images that are defined in terms of points on a Cartesian plane, which are connected by lines and curves to form polygons and other shapes. Vector graphics have the unique advantage over raster graphics in that the points, lines, and curves may be scaled up or down to any resolution with no aliasing. The points determine the direction of the vector path; each path may have various properties including values for stroke color, shape, curve, thickness, and fill.
Instead of sectioning off a large region of computer memory and mapping that to the display device, vector display devices use a variable number of lines to create images—hence the term “vector graphics.” Since vector display devices can define a line by dealing with just two points (that is, the coordinates of each end of the line), the device can reduce the total amount of data it must deal with by organizing the image in terms of pairs of points.