Images

1. What is a pixel?
A pixel, also known as picture element, is 1 single square out of a thousand or so, that makes up a picture. Usually when you zoom into a image on the computer, the picture quality isn't as good because you can see all the pixels, which are squares. Each of the pixels are a colour and many of them are usually different colours or shade of colour. All of the different coloured and shaded pixels make up all of the detail on the image when you're not zoomed in.

Image of computer (Normal and zoomed in)

The image on the left is normal but when you zoom into the image (Image on the right) you can see that some of the pixels are now showing.

2. What is resolution?

Image resolution gives out details about the image such as the size of the image and how many pixels it's made up of. The higher the resolution means the more detail the image has (bigger the image). E.g. if the image's resolution is 200 x 250 pixels, you can times the two numbers together (200 x 250 = 50,000) and it will tell you how many pixels there are all together in the image, in this case it's made up of 50,000 pixels. 72 - 100 DPI (Dots Per Inch) images are usually used on the Internet; 300 DPI images are for printing.

3. What is Bitmap / Raster?

Bitmap / Raster uses pixels to display images. The quality of the image will usually be pleasing enough for the human eye, but when you zoom into it, the quality won't be any good because the pixels will become more noticeable. Each pixel holds a single colour and it can display loads of different colours; this will show plenty of detail, which is why it's really useful for photos.

4. What is a Vector?
Vector doesn't use pixels; vector uses mathematical lines, shapes and polygons to display the image. This is good because when you zoom into it, the quality of the image will always stay perfect. However vector can only be used for basic graphically drawn images on the computer and nothing too complex such as photos.

Vector drawn image

This is a image of an apple and although it does look quite realistic; it isn't real. Vector is very good for displaying logos and cartoon images with perfect quality.