I am very sorry for your situation. I have some advice that may hopefully help you.
First, when the pictures of your parents and the things that they did to you flashes into your mind, you are most likely to follow your stream of thoughts and get angry. Once angry, you smash things as that is your habit. The best way to stop this is to be mindful of the anger that is arising; mindful of how the anger which has not yet arisen comes to arise, and mindful of how the anger which has already arisen ceases by itself. You can imagine yourself as a chemist. A chemist only WATCHES the chemical reaction going on but he himself never jumps into the reaction! You should do the same when you know that your anger is about to start. Try to watch the anger; watch how it arises and how it ceases. It's just like watching a play. DO NOT think along with the stream of angry thoughts, even though the anger is like Mara trying to lure you into its stream of angry thoughts. When you try to be mindful, you may notice that the emotion is trying the best to get you thinking along with it by reminding you how horrible your parents were, or what they did, or how badly you were affected. But DO NOT jump into this, because once you start to think along with it, it would be hard for someone to get you out of the anger. You would get carried around by the stream of anger and probably do things that you regret while not angry. Even when someone tries to calm you down, when you are angry, you would not even try to be patient or calm down! You just want to let the anger out or hurt your enemies to satisfy your anger. Also, when you are angry, people who try to logically calm you down by giving you advice would also fail; because anger does not respond to logic! So next time, when the pictures of the things that your parents did to you flashes in your mind and comes into CONTACT with your mind, before it is too late, start applying mindfulness and watch your anger and emotions. You would find out that as soon as you watch the emotion, it will shyly disappear. Now once it disappears, do not think about your parents again, because anger can continue to come back again and again after painful images come in contact with your mind! I have personally experienced anger coming back repeatedly. So overall, watch your emotions, apply mindfulness, and let it go by itself. Watch it mindfully as it arises dependent from contact, and how this anger ceases by itself.
Don't be angry at yourself because you got angry. The Buddha said that feelings are not "the self." Why? Because for example, when you are experiencing an unpleasant feeling like anger, you take that feeling as the self. Later, you might experience a pleasant feeling like joy and you also take that as your true self. But these feeligns are impermanent and cease at some point. If you take these feelings to be your true self, it means that your "self" has also disappeared along with the feeling that you take as the "self." Also, when you are angry, you might smash stuff. But when you are not angry like right now, you regret having smashed stuff and you seek ways to solve your anger problem. This clearly shows that neither of the two states that I mentioned is your actual "self." So feelings change all the time, and while experiencing a feeling, you take that feeling as your self, but it is not. So don't get angry at yourself.
Your habit of smashing stuff while angry is because every time you get angry, you tend to do that. So by using mindfulness and not getting carried about by your anger and letting it go, that habit will eventually stop. This is also true why some people get angry easily; it's because its has become a habit to get angry and act on anger every time they get provoked. I think that if they use mindfulness and just let that anger go, that habit will eventually stop.
After you have mastered the method of mindfulness to stop your habit of becoming angry a lot and smashing things, I suggest you do metta meditation. Metta is the direct antidote to anger and hatred. At the final stages of metta development, you can develop metta to people who you have difficulty with; in this case, your parents.
Good luck! I hope this helps.