Any help appreciated! Can I fix an image in position when scrolling on custom product page (Envy)

Hi everyone,

I would like to make it so that when users scroll down on the right to select custom product options, the product image on the left follows them down. At the moment once the product image stays at the top of the screen, meaning users would have to make a change then scroll up to see the altered product example.

Here’s a link to the page/website: https://thebespokesignhouse.com/products/engraved-honed-slate

Here’s a couple of pictures showing what I mean.

Does anyone have any idea what I need to do? Please let me know if any further info is needed.

Many thanks in advance!

Kris