This mod lets users easily change the game start menu artwork.
Details
To change the background, you simply replace the .png files in UIAtlases/ItemIconAtlas with those of the same size with those you want to use.
Changelog
A20 conversion.
Download for A20
Download for A19
The forum topic of the mod is here.
Credits: Khelldon, Doughphunghus
I cannot find UIAtlases/ItemIconAtlas.