Whats the difference between highball glasses and double old fasshioned? Anyone?

We resgistered yesterday and we want to put some barware down along with our wine goblets and glasses. Can some one please either post a pic or try to explain the difference. i know this might seem like a silly post but i would hate to register for something i dont want!! Thanks.

isn't one of them the shorter and one of them the taller - like a regular glass and then like a juice glass type thing?
not sure which is which!!

THe highball glass is a tall glass used for drinks such as soda, water, ice tea.
The double old fashioned glass is used for mixed drinks.

i was close.....