Each object can be moved, modified, or deleted without affecting other objects in the image. Since the objects of an object oriented image are represented by mathematical equations, the image can be scaled to any size without a loss of quality. Architectural and engineering drawings are usually object oriented. Bitmapped images, also known as raster images, are more like a piece of graph paper, where any square of the paper has either been colored in, or not. Geometric shapes can be drawn in a bitmapped image, but once drawn, they have become an integral part of the whole image, and can not be moved without affecting the area of the image they occupy.
Bitmapped images are ideal for representing photographs or paintings.
Object oriented images can be converted into bitmaps, sacrificing the independence of the objects. Since the vast majority of images that can be displayed by NCSA Mosaic or are otherwise commonly available on the Internet are bitmaps, this document concentrates on bitmapped image technology. You can think of a bitmapped image as a piece of graph paper, of any size, that has had each square filled in by a color. In computer jargon, the squares are called dots or pixels. The term pixel was derived from the term picture element.