What is the difference between vector and raster objects?

Raster objects are made up of pixels and are considered resolution dependent because they contain a fixed number of pixels that are used to create the image. They will lose quality if enlarged beyond the number of pixels needed in a particular use. Since there is a fixed and therefore a limited number of pixels, the image becomes fuzzy as it is enlarged. Raster images are the best choice for creating subtle gradations of shades and color, such as in a photograph or in a computer-generated painting. Vector objects are made of lines and curves that are defined mathematically in the computer. A vector graphic is resolution-independent. They can be made larger or smaller without any loss of quality to the image. Vectors can be printed at any size, on any output device, at any resolution, without losing detail and without altering the resolution of the image.