Shocks & Springs Idk

[Tigere313]

So I have a 2000 Mazda Protege 1.8L DOHC, and for some reason my left rear is knocking I'm guessing it's the shocks but how can I actually know or find out if the shocks are bad and what do you suggest the kind of shocks or whatever I need is to get

Below are images of my car

http://imgur.com/bdArp9v
http://imgur.com/KLr6sIx