Pixels versus vectors Digital photographic images are constructed of a mosaic of pixels and as such are resolution-dependent. If you enlarge such an image beyond the size at which it is meant to be printed, the pixel structure will soon become apparent. Therefore, you can only scale the finite pixel image information so far before the underlying pixel structure becomes apparent. By contrast, vector objects, created in programs like Adobe Illustrator (as well as Photoshop), are defined mathematically. If you draw a vector shape, the proportions of the shape edges, the relative placement on the page and fill color can all be described using a mathematical description. An object defined using vectors is therefore resolution-independent and it does not matter if the image is reproduced on a computer display, a postage stamp or as a huge poster, it will always be rendered with the same amount of detail (see Figure 4.1).