hopefully you can help.
My website: www.chromahouse.com

I am trying to set a full screen background image to a number of specific pages (about 5-6 other pages)

The link to the image I want to use: https://www.chromahouse.com/wp-content/uploads/2019/07/purpleandblue.png

An example of a page I would like the full screen background image to be on: https://www.chromahouse.com/about-chroma-house/

My plan is to remove the featured image you see on the header of these pages and replace it with the background image but in a way that it covers the entire page from header to footer.

Any help is appreciated!