Raster And Vector Research

http://vector-conversions.com/vectorizing/raster_vs_vector.html - I thought this link was very useful, and a good piece of research to use because it gives you the disadvantages and advantages of Raster and Vector, and it tells you what they are best used for. It also gives you useful knowledge  and understanding of what they are.

Raster images are made of pixels. A pixel is a single point or the smallest single component in a display device. Let's think of them as little tiny squares* or dots of color or shade.
Vector images are mathematical calculations from one point to another that form geometrical shapes. Vector graphics also display an outline or wireframe view and this is very important for certain processes.
When a raster image is scaled up, it usually loses quality. A raster image can be enlarged by either adding more pixels (which Photoshop randomly - but smartly - adds) or enlarging the size of the pixel. Either way you are spreading the original data over a larger area at the risk of losing clarity.
A vector program will use a mathematical formula to build an image that can be scaled to any size without losing quality. Raster images are also called Bitmap images, pixels are also called dots, and dots-per-inch (dpi) sometimes called pixels-per-inch (ppi) although technically they have distinct meaning I may use those terms interchangeably in this website.
Raster images' dimensions are measured in pixels. Because raster images cannot be enlarged without losing quality, different suppliers have specific size requirements for their processes; they require a specific pixel resolution: a specific amount of pixels within each inch. The amount of pixels within each inch in the image represents the image pixel resolution or ppi (pixels per inch).