Dragonfly or Damselfly?

~backblip~

So it was a toss-up between this picture, taken by the goofy boyfriend, or a picture of said goofy boyfriend mounting a giant wooden caterpillar. Tough choice :P

Anyone want to tell me the difference between damselflies and dragonflies? I know they're a little smaller, but surely you could just call them mini-dragonflies?!