Digital images can usually be divided into two distinct categories. They are either bitmap files or vector graphics. If you work with CAD, you will need a good understanding of the advantages and disadvantages of both types of CAD drawing techniques. As a general rule, digital pictures and scanned images are bitmap files. These are sometimes also called raster images. Drawings made in applications like Adobe Illustrator or Corel Draw are saved as vector graphics. Technically both data formats are completely different. The end result, however, can look virtually identical in either format. As a general rule bitmaps are typically used to depict lifelike images whereas vector graphics are more often used for abstract images such as logos. There are however numerous exceptions to this rule. It is often impossible to determine whether an image is a bitmap or a vector file just by looking at it.