When artwork is created as vector art (normally in something like Illustrator or CorelDraw creating .AI or .EPS file formats) it is created something like a blue-print.  This blue print can be read by software such as Adobe Photoshop, Illustrator or Corel Draw.  Unlike Bitmap artwork (JPG, GIF, etc.) which is just an overall picture of an image, a vector art image tells the graphic software how to actually draw the image.  Where to put specific lines, dots, and other values. So no matter how big or small the artwork is, the graphic software is told where to place the individual components of the artwork so that it does not lose it’s detail Vector artwork is always the highest quality.  This is because the image can be opened at any canvas size for any purpose.