Pixel images

Pixel images are formed by a rectangular grid (also known as a bitmap or raster) of small squares, known as pixels. Each pixel in a pixel image has a specific location and contains data that describes whether it is black, white or a specific color value.

For example, a slanted line of a pixel image is composed of a collection of pixels in a specific location, of which pixels A7 and A8 are black, B6 and B7 are black, etc.

Figure 1. A bitmap representation of a slanted line.

You can edit a pixel image by altering or manipulating pixels or groups of pixels. To do this, you need image editing software, such as Adobe Photoshop.

Pixel images are resolution-dependent because the number of pixels that describe the graphic is fixed. Scaling a pixel image will not change the absolute number of pixels, but will change the number of pixels per square unit of measurement. Consequently, pixel images can appear jagged or lose detail if they are enlarged or printed at a higher resolution than they were created for. Pixel images are also called raster images.

Figure 2. Pixel images describe shapes in pixels.