How to make two images superimposed on each other in fluid layout dependent?

Question

css

The two pictures are superimposed on each other by means of a layer control (z-index).
How to make that when scaling and resizing the browser window, they move together without changing the size?

Answer 1

on the div, the sizes are fixed, the sizes of the images are relative to the size of the container. Because container dimensions do not change - image dimensions also remain constant.
That's just with scaling it's not so easy to ride. If you want - use js and catch changes. in jQuery $(window).resize();

Answer 2

stuff them into a common div block, position:relative block

Answer 3

https://codepen.io/search/pens?q=canvas+particles&...