The easiest way to explain a Vector image, is to show you the difference between a vector image and a raster image.
What they are:
Vector = Path-based, which means made of a bunch of mathematically precise points
Raster = Pixels (aka just bunch of little dots)
What makes them (generally speaking):
Vector = Adobe Illustrator or Corel Draw.
Rasters = Adobe Photoshop, Paint, Word, etc.
“Claaaaass, thoughts on why this matters for a Logo? Anyone? … Anyone? …”
Vector files can be enlarged to as big as you want and you will not lose any quality of the image! Woot!
Raster files (aka bitmaps) can only go as big as they’re made, any larger and they get all pixelated-looking. Bummer, dude.
See the excellent example below.
This is why all correctly designed logos are in a vector format, so you can make them as big as a plane or small enough for a pen and they still look like awesome sauce!
Good to know: Every image that exsits on the web and all photographs are RASTER. That is why you can’t pluck a photo from online, enlarge it and print it on a full sheet of paper without it looking like doo doo.