Gets or sets the format in which Mathematica graphics will be rendered.
The default value is "Automatic", which tries to provide a good compromise between speed and quality for most graphics. When the setting is "Automatic", GIF will be used in most cases, JPEG in some.
You are encouraged to try "Metafile", which uses the Windows Metafile format. These images can be dynamically resized after they have been created, and will redraw in excellent quality at any size.IKernelLink Interface | Wolfram.NETLink Namespace