What is the differeance between Rasta and vector?

Raster images are defined in pixels. ie At every x,y location, whether it is black or white.

Vector images are defined by lines. eg From x,y to X,Y. Any pixel that lies between these points on a white background becomes black.

It is easier to convert Vector images to Raster images, rather than the other way.

Vector images are sometimes smaller (in data size). eg If the image contains one line, then the amount of data needed to store this is smaller than having to define every pixel in the image regardless of whether it is relevant.

Vector images can be scaled smaller and larger without any significant loss of detail. Raster images that have been made smaller lose clarity and cannot then be made larger to improve the quality.