Each one has its own special place in the world.
Raster editors are probably the most common graphical editing programs.
They edit graphics using a bitmap of colors, or pixels. Raster images are generally large because every pixel has to be saved, yet they're more detailed because every pixel is saved. Examples of Raster programs include Paint Shop Pro and Photoshop. Vector Graphics are a little different from raster. The file sizes are very small because instead of every pixel being saved, the methods to render the images are.