Computer graphics are stored as either raster or vector images.
In a raster image, also called a bitmap, a picture is represented as a rectangular grid of pixels, each of which is assigned a color value. Photographs and scanned images are saved as bitmaps. If a raster image is enlarged to the point that individual pixels become visible, it will appear grainy, with jagged edges. Higher quality raster images require larger file sizes with higher resolutions.
Programs: Adobe Photoshop, GIMP, Microsoft Paint
File formats: JPEG, PNG, GIF, BMP
Vector graphics are represented with basic geometric structures such as points, lines, curves, and polygons. These shapes are stored as mathematical equations. Vector images are used for graphic design, including logos, text, and clipart. Vector graphics can be arbitrarily magnified or reduced with no loss of quality, while retaining their crisp, smooth edges. Vector files are usually smaller than comparable raster files, and a vector image’s file size remains constant regardless of scale. Discrete objects in vector drawings can be individually moved, scaled, rotated, and otherwise manipulated.
Programs: Adobe Illustrator, CorelDRAW, Inkscape
File formats: PDF, SVG, AI, EPS