Replace current base background screens

[Mr. Quiet]

I would like to add these pictures into the game and replace the default ones:

https://poibuts.deviantart.com/art/Xenonauts-Workshop-429877816

I'll edit it so I only have one screen. What do I do to get this done? I'm also gonna try to make it pixelated to match the base layout and colors, if I have the time. For now I just want to know how I can replace the backgrounds with these.

Btw, the link has spoilers for the upcoming Xenonauts game. It shows different versions of the Workshop as you're taking in more alien technology. I kept my eyes closed and edited out the rest of the screens fast I hate spoilers.

[Shoes]

I know one problem you will run into will be the colors. You will need to use these colors : https://www.ufopaedia.org/index.php?title=PALETTES.DAT#UFO

My suggestion would be to use the same colors as the image you will be replacing. Then maybe just replace the old file? You could probably also make a new ruleset if you want to be "proper".