I'm trying to recreate an effect that I'm guessing employs some combination of CSS/JS:

I want a fixed position image to stay sticky on the left side of the page while paragraphs of text scroll to the right of it. The image would change depending on which paragraph of text is visible in the browser window.

Recording of a website that does this well: https://www.loom.com/share/39a65ff6d668485a89b1e2e25b2a11c9

In this example the text also changes color depending on where it is in the window. Any help or insight into how simple/complex this is would be appreciated!