Of course, if you want to choose one of your own photographs, pictures or an image you find on a website as your background, find the image and right-click on its icon. Choose "Set image as desktop background" and it will become your new theme. To save it as a theme for future use, open the Personalize option again and click "Save theme." Now you can reuse it again and again without having to hunt for the original image. Plasma can often be called the fourth state of matter, after solid, liquid, and gas. It is also sometimes described as an ionized gas i.e. a gas when the degree of energy is really high how the electrons escape from the atoms. This leads to soups of charged particles that happen to be overall quasi-neutral.