Putting Down Animals?

I don't agree with it, but regarding animals who attack people what would you suggest as an alternative?
Society would freak out if nothing was done to a dog that killed a young girl. Sure the dog isn't evil, but instinct is real, and accidents can happen. Regarding over crowding of shelters, I think that's absurd. There's always alternatives but people tend to take the easy way out of things in such situations. It's unfortunate that animals do get put down frequently in said situations.