22 Working with Images
An image is simply a rectangular graphical object. It is simply a 2D array of pixels. To a computer, an image is just a set of numbers. The numbers specify the colour of each pixel in the image. The numbers representing the image on the computer's screen are stored in a part of memory called a frame buffer. Many times each second, the computer's video card reads the data in the frame buffer and colours each pixels on the screen according to that data. Whenever the computer needs to make some change to the screen, it writes some new numbers to the frame buffer, and the change appears on the screen a fraction of a second later, the next time the screen is redrawn by the video card.
Since it is just a ...