Answer:
Rastor images/Bitmaps are images that consist of individual pixels. Memory is a pixel image file format which uses a low ammount of memory due to poor quality. When you emlarge a pixel it reduces the resolution. This would be a good example. Bitmaps are used for windows based systems because it is a basic file with low memory usage.
Vector images consist of indivual shapes and use a low ammount of memory because it is a simple image like a drawing used by shapes. you can modify it without losing quality. Vectors are good because they are a small file size wth unlimited zoom without loss of quality, but they cannot produce photos well. Vector images are used for myspace sites or used as a background in a default picture.