Hi @VanDijk, I can’t see the pictures in the codepen you posted (I’m using the phone to connect to codepen).
Make sure to close the img tags like this:
<img src="…" alt="…" />
Instead of using the image as an element and having to implement something for positioning and z-indexing, you could treat is as a background for the div (check the CSS properties for backgrounds). That way you will easily be able to write on it. While you do that, do consider that the text and the image below it need to have a good contrast in order to provide accessibility to people with vision problems.
Edit: basically you could do something like this:
By default the image is repeated both horizontally and vertically. With the
background-repeat: no-repeat; you prevent that.
background-size: cover; the image will be stretched or cut to fit the div to which it is applied.