Art by Pixels and Numbers

By now you might be wondering why you need to understand a pixel in such detail. The truth is, when you can manipulate digital images at a pixel-level, you can do a lot of artwork simply by twisting the numbers behind them.

A good example of this is a filter found in Adobe Photoshop called the Custom Filter (Found under Filter -> Other -> Custom):

There is a lot of complicated mathematics behind how this filter works. If you are interested in understanding this filter, take a look at the Photoshop CS Bible.

Each white cell carries a weight. The middle white cell is the pixel that we are manipulating.
As you fool around with the numbers, pixels get manipulated differently, producing different outcomes. The following are some simple examples:

Invert Colors

Blur

Notice that the scale is the sum of all the weights. That makes sure that the image does not become darker or brighter than before.

Random Numbers

After randomly typing in numbers, an outline effect was created similar to Filter -> Stylize -> Glowing Edges.

You can find a lot more examples of the custom filter tool in use here.