Custom Logo
Make your logo with transparent background.
Dimensions: 960 x 265
File name: main_menu_logo_960.png
Resize it to 480 x 132, save as: main_menu_logo.png
Put these 2 files into /YOUR_MOD/GUI/SpriteParts/YOUR_SPRITE_CATEGORY/General/InitialMenu/
Make sure YOUR_SPRITE_CATEGORY is configured in /GUI/Config.xml as described here.
Import these pictures and you will get your logo in the game.