If I remeber correctly, when we went to BB last June, we "rented" towels for $1 each. They were plain white--about bath size. It was actually nice not to have to lug our own towels to the park--we barely used the ones we rented, too. We didn't carry them with us between slides, etc. They just stayed at our lounge chair.
We DID use a waterproof disposable camera (had an elastic wristband) and got great photos!!