File Format Fundamentals
Graphic images – such as photographs, illustrations, drawings, logos, and clip art – are a great addition to any printed piece. When combined with text, images measurably increase reader comprehension, retention, and interest when compared to text only. In printing and publishing, graphic images are two-dimensional (2D), while on the web images can be two- or three-dimensional (3D) or multimedia.
There are two ways to form graphic images: pixel by pixel in a grid (called a bitmap or raster image) or mathematically from geometric objects such as points, lines, curves, and polygons (called vector images). Digital photographs and all images that have been scanned are bitmap images; vector images originate primarily from illustrations or drawing software programs or from plotters used in technical drawing.