Raster vs. Vector Graphics

Graphic files come in two types: vector and raster. Most of the photo editing programs primarily work with raster graphics and some of them are additionally capable of reading (and saving) vector file formats.

Raster Graphics

Raster files store graphics as bitmaps, sort of like a graph paper. There are no objects, only information is there about what color each square (bit) of the picture should be. Bitmap images (.bmp) is the most common example of raster images.

Vector Graphics

Vector files store graphics as objects which is described by mathematical relationships between points and the paths. Each graphic file internally contains a small list that describes the shape, colors, outlines, and sizes of the objects that make up the graphic. This list of vectors enables the graphic to be drawn on screen or rendered to a printer. These kinds of objects are easy to resize as all of their other characteristics stay the same. For example, if an object is a circle, it’s the same circle whether it’s small or large.

Pros and Cons

1. Scaling
   Now a days an ordinary PC usually displays fonts and images, treating them point to point instead of the pixels. Consequently, when a vector image is scaled up it seems clearer and smooth while in the case of raster image serrated edges and sharp notched are appeared. If you notice the fonts you daily use then more often these will be True Type which are vector based.
   
   
2. Size and Resolution
   For the smooth display higher resolutions and anti-aliasing is required by all bitmap images. On the other hand, as we know vector graphics use mathematical description so they support higher resolution with the minimal size.
   
   
3. Usability
   In the graphics work vector, images are not always appropriate because of their limitation of usability. For instance imaging devices e.g. scanners and cameras produces raster graphics which cannot be converted into the vector graphics. So people will like to treat the pixels instead of drawing the objects. Bitmap graphics are more appropriate for photo processing, montage, retouching, photo-realistic illustrations and the handmade illustrations or with a pen tablet.
    

Application Softwares

Most popular raster editors (or bitmap editors) are GIMP (which is best open source imaging software) and Adobe Photoshop also provides the specialized tools for vector image processing. Whereas some of the popular vector editors like Adobe Illustrator, Adobe Fireworks, CorelDRAW, Xara Xtreme and Inkscape now have built in tools for raster images.

File Formats\Extensions

Raster Graphics

.psd (Adobe Photoshop)  .jpp (JPEG Raster File Format)  .gif (GIF Transparent File)  .PNG (Portable Network Graphic Transparent) Vector Graphics .art (Adobe Illustrator graphics) .cdr (CorelDRAW vector image) .dvg (GraphicsWorks vector drawing) .dxb (AutoCAD drawing exchange format) .fh10 (Adobe FreeHand 10 drawing file) .ps (Adobe PostScript file) .plot (Vector graphics) .pat (Corel vector pattern) .svg (XML based vector graphics format) .xar (Corel Xara drawing) .wmf  (Windows metafile)