Bitmap and vector graphics
There are two main graphic types - bitmap graphics and vector graphics. Bitmap graphics are made up of pixels of different colours. Vector graphics are made up of objects.
When you take a photograph using a digital camera or scan an image from a magazine, you are creating a bitmap graphic.
A bitmap graphic is composed of many tiny parts, called pixels, which are often many different colours. It is possible to edit each individual pixel.
Since the computer has to store information about every single pixel [pixel: One of the individual units (often called dots) that make up an image ] in the image, the file size of a bitmap graphic is often quite large.
When you resize a bitmap graphic, it tends to lose quality.
Use the slider to zoom into the bitmap graphic below. Notice how as you zoom further in, the image loses quality and you can start to see each individual pixel.