Liquid crystal display or LCD digital screens are made up of tiny liquid crystals (LCs) that shine either red, green or blue light (RGB). Digital images also use pixels, but use a wider palette of colours. Internet images such as jpgs or gifs work with 256 web colours to create all the images, illustrations and web content online. Pixels work on a simple grid format with lines of equally-sized squares. The blending of the colours takes place visually, with pixels being too small to be easily seen by the naked eye.
In the early days of digital images pixels and the rough edges they create were more evident and consequently more a part of the visual language of computers. Certainly early computer games had this very squared, pixelated feel to them and many artists and illustrators used this way of working to represent the digital.
These drawings can be produced on graph paper, or digitally on computer in Adobe illustrator or in iPad software like Sketchclub and ArtRage.
It is possible through simple variations in position and colouring of pixels to get a wide range of different characters in an interesting way.
See 7 Billion website of linked pixels. Can I do a face eg of champions on-line like this?