vector vs. raster graphics
Digital graphics can be created as either raster or vector.
Raster graphics are basically a collection of lots of tiny squares, or pixel. Each one has a specific shade, and put together with thousands of other pixels, create an image.
They're best suited for photographs and graphics that are to remain small in size. Why? Because these are made of pixels, the more they are blown up/increased in size, the more image degradation you can see. Suddenly the image is blurry and jagged!
How can we avoid this? If you're taking photos, for example, make sure your camera is set to capture them at the highest resolution possible. (Resolution is measured in dots per inch, or DPI. The higher the DPI, the better the resolution.) Better resolution, however, comes at a price. The files can be quite large in size and are slower to display and work with.
Common raster file types are JPG, TIFF, GIF, and BMP.
Vector graphics, however, are based on mathematical formulas.
Because of this, they are better suited for graphics with fewer tones and more flat, uniform colors, like logos, shapes, and fonts. Why? Since they're based on geometry instead of pixels, they are very crisp and can be blown up to infinity size and not lose resolution.
Due to the absence of complicated collections of pixels, these files tend to be considerably smaller than raster images.
Common vector file types are AI, EPS, SVG and sometimes PDF.