Vector graphics use maths to store the data on shapes by breaking them down into a series of lines, shapes and colours. These can then be manipulated by stretching, twisting and adjusting the colour with no loss of quality. Although vector graphics deliver very sophisticated and useful results, many people would be surprised to know they were first used in 1963 in the very earliest home arcade games.
A computer generated image uses pixels, which means that it will eventually break down into its component squares when enlarged. This is not a good way of creating an image that will be used, for example, on billboards.
An image designed using a vector graphics programme can be enlarged infinitely without decline in quality. Due to the information being held as a series of mathematical formulae, the file size will never become too big to use.
Fonts are typically stored as vector files, because otherwise the operating requirements would be too much for the average PC and creating a document would take up a huge amount of memory. Editing a vector graphics image is easy and does not use-up much memory either, because it is only converted to a bitmap if necessary for transferring to another device. This means that unless exact photo-reality is required, vector graphics are a very user friendly way of designing and manipulating designs.
Vector graphics deliver very good quality if an image needs to be zoomed in on, and printing an image created as a vector graphic gives a very crisp result at any size without pixilation. Shading is very realistic using vector graphics, giving a superior 3D effect, even at magnification.