We live in a world filled with pixels. Although we may not think about it very often, we see innumerable images made up of tiny little squares throughout the day.
Adobe Photoshop and the other CS2 applications work with bitmapped (otherwise known as raster) images. The easiest way to think of a bitmapped image is as a grid of pixels (see Figure 4-1). A pixel is a “picture element,” and it’s the basic building block of a bitmapped graphic. When pixels are stored, they are saved into a raster file format.