In graphic design, there are two distinct file types: pixel and vector. The advantage of vector files is the ability to stretch to any size larger or small without have any resolution loss. So why isn't everything a vector file? Anytime you use a camera, the chipset creates the picture with pixels and, as of now, there's no way around that. On the positive side, cameras and even camera phones offer top quality pictures with many psi (pixels per square inch). The higher this number, the better the quality and resolution of your picture.
The following illustrations are all vector-based graphics built using Adobe Illustrator.