Computer graphics are created in one of two formats: vector and or bitmap. Computer files containing these graphics may contain vectors, bitmaps, or both.
Vector graphics
Vector graphics are created by using mathematical algorithms: formulas that describe where points, lines, and planes exist and how these elements relate to one another. Vector graphics can be scaled up to any size and retain their smooth edges. Logos are best done in vector graphics because the graphic can be scaled from the size of a business card to large billboard with out losing clean edges. Adobe Illustrator and Flash are applications most often used to create and modify vector images.
Bitmap or raster graphics
Bitmap or raster graphics are built from grids of pixels. Each tiny pixel contains a unit of color information. Bitmaps are used for digital photography and scanned images. Bitmap files are not as easily scalable as vector graphics. Bitmaps provide a smoother transition of color and value than vector images.
BMCC Art 100, Professor Reinhardt 