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Pixel (aka bitmap or raster) based images are those constructed of pixels (picture elements) and are resolution dependent. The number of pixels an image contains is linked to the resolution setting.
Once the resolution is set only resampling the image will create a larger image, however this technique will not achieve the effect of a true higher resolution image. (see 'Image resolution' for more information)
Files using pixels are able to produce continuous tone images, where all variations of colour can be represented as a single tone of data. This digital process replicates the effect of a photograph so that the human eye sees an image with unbroken colour transition.
Vector based images are defined by mathematical equations and are resolution independent. Files are scalable to any size and therefore print at optimal definition at all times. Content is constructed from lines, shapes and curves which are formed by bézier paths defined by nodes and control handles. A vector image can be rasterised into a pixel file, however the reverse conversion is limited and determined by both image content and available software.
Typical vector created files includes corporate logos, charts, diagrams and illustrations featuring content not requiring specific photographic techniques. Elements are constructed with both stroke and fill attributes, created from flat colour, blends, tints or gradients. Vector images also feature no inherent background (as pixel files do), so transparency can be easily created when placing in other applications.
