The term "vector clip art" refers to a collection of images that are stored electronically as mathematical formula. A vector image from a computer point of view is a mathematical map of lines, points, polygons and color information. Together, this data serves as a set of instructions for rendering the image in visual form on a computer monitor or to a printed paper copy.
Vector clip art images have several unique advantages over their counterpart, raster images. They are scalable, which means that they don’t lose resolution or clarity when increased in size. They also are generally much smaller and faster files to load to a web page, or to download, than raster images are.
Raster images are a pixel-by-pixel true life representation of an object or scene. This is why photos have generally always been stored as raster images. Vector clip art used to consist primarily of images that contained far fewer colors than the millions of colors that can be present in a typical raster image. An example of this clip art limitation was the early graphics interchange format (GIF) file that contained a maximum of only 256 colors per image.
Vector clip art today can approximate the real-world look of a photo by use of complex equations that mimic three-dimensional effects, lighting and shadow. A vector image’s size, angle of view, colors, textures and other properties can all be changed without distortion using modern computer graphics software. Such flexibility with raster images is not practical, because any alteration in a raster image’s size or shape will permanently add or delete pixels from the original file, resulting in distortions to the image that cannot be undone.
One of the most popular uses for this type of clip art on the Internet is in animation. Vector animation programs can provide elaborate, photo-realistic effects for websites. The animation is stored and transmitted as a collection of calculations that computers can process much faster than raster images could be rendered to a screen from memory.
Vector clip art is easy to produce and transmit, so many websites contain copyright-free collections. Aside from content such as pictures of people, animals and inanimate objects, the vector process is also used to create background graphics for the web. Things such as interactive buttons, menus, background layouts and color schemes are designed using clip art galleries. In addition, many modern online games are designed based entirely on the use of vector clip art.
