I want what happens on picture one to happen on picture 2 aswell, even though the blue bar stretches out, but wanting to keep them as children of that image; see below.
To prevent stretching all four anchors need to be placed on the same location. For your example I would suggest anchoring the left button to the LHS, the middle on to the center and so forth.
You can also use the layout elements to achieve the same effect. Here is one of my videos that uses them. You may need to play around with the settings to achieve this.