How to make a wobbling effect in CSS (or js)? [closed]

How to make a wobbling effect?

see this animated image:
Wobbling background

1. Question

how to create such an wobbling background effect in JavaScript and/or CSS? Does anyone have a sample code?
It is built atop of such a image:
background img

2. Question

I have neither a clue how this effect is named. Can someone help here too?