4. Image types: vector graphics

Sometimes it is very useful to be able to change the size of an image without losing quality.

This font for example can be made in many different sizes.

Notice that the shape of each letter is still smooth no matter what the size.  You can make it as large as you like and it will not pixellate or go fuzzy like a bitmap image would.  This is an example of a VECTOR IMAGE. 

Instead of storing every single dot in the picture like bitmaps do, vector images store a set of instructions of HOW to draw the shape.  For example, look at the line below - this is a vector graphic:

      a ____________ b

The instructions would be something like this:

1. Draw a dot at point "a"
2. Draw a dot at point "b"
3. Connect the points together with a straight line
4. Colour the line red

The size of the file does not change if the image needs to be larger - the same instructions will make the image as large as you like, and yet the line would always remain smooth and clear.

Some images are not suitable for storing as a vector image. For example, a detailed photograph would need so many vector instructions to recreate it, that it is better to store it as a bitmap.

On the other hand simple geometric shapes such as letters, autoshapes and logos are ideal for storing as vector images.