A paint program works with pixels whereas a drawing program works with vectors. A pixel is a picture element, and collectively those pixels make up a raster image. Programs such as Photoshop, PaintShop, and PhotoPaint all work with pixels or raster images and therefore fall into the paint program category. Vector objects are made of lines and curves that are defined mathematically in the computer. Programs such as PowerPoint, Illustrator, Freehand, and CorelDraw all work with vectors and therefore fall into the drawing program category.
Vectors can have various attributes such as line thickness, color and length.
For example, in a drawing program, a square is drawn as four lines connected at the corners. Those lines can be set to different thickness and colors. The square can be hollow or filled. A line is one object with attributes, and you work with this line as a single object, not as a group of pixels as you would in a paint program. You were enlarging vectors when you did that.