Raster vs Vector. The quick version.
Here are two images, can you see a difference? Well, one way you can tell the difference is either zoom in really close on the image or try to enlarge the drawing. Let’s see both…
Image on the left is a Rasterized image. Raster image is an image that is created by laying down dots called pixels to form an image. Normally these images are created by scanning an existing image or creating the image in a computer with photo editing software or a drawing program. The draw back to a Raster image is the size you scan or create it at is the size you should keep it at. Simply put, what you see is what you get.
The right Illustration is a Vector based image which is created by drawing with a vector illustration program like Adobe Illustrator or CorelDRAW. Vector images are based on geometrical primitives shape such as points, lines, curves, or polygons. Vector graphics are made of mathematical calculations so they don’t use pixels making them infinitely scaleable without losing quality.
So what should I use for my image?
It really depends on what your trying to create. If you want an image with lots of detailed elements, blends of color and crazy effects you should use a paint program like Photoshop, Painter, or Sketchbook. If your final image can be a little simpler with clear contrasts between objects & shapes, then a vector program is the way to go.