See this page: https://design.google/library/managing-ambiguity/#encourage-artistry-around-the-office

You will notice that the left column image is replaced a new image that quickly fades in over it as the right column scrolls.

Does anyone know how to make a new image appear over an old image in this manner?

In a previous thread, I sought ad how to accomplish the two-column side by side parallax scrolling in the "design.google" example above. Thanks to both Rene and Wayan Jaya for helping. You can see that thread here:
https://www.coffeecup.com/forums/site-designer/does-anyone-know-how-to-do-side-by-side-parallax/

If u saw my previous demo the that effect can be incresae by the transition timing and fixing the background image to position fixed

Hi