pianoplunker is right. Your wrists are way too low. There's a lot of tension in your fingers, you gotta relax them. You may be able to find your way through easy pieces, but once you tackle harder ones, it'll be hard to play like this.
Are you self taught?
First, thank you for the replies.
I had lessons when I was little but I didn't play anything for a very very long time so yes, I think I am considered as self taught.
And about your advices, I can not play properly when I hold my hands like the text-book-ball-holding position. Could it be because my fingers are not strong enough?
Or could it be because I'm sitting too low in front of the keyboard, as you can see I don't have an acoustic piano. Would it get better if I sat higher maybe?