As long as you followed all of the directions, it should just work if you slip it inside of your main menu definition.
Can you tell me what version of Ren'Py you're on? I can see if I can reproduce issues with the directions.
I'm using 8.5.3. When i try to paste It anywhere inside of main menu() in screens and delete the active background line, when i launch the game there's just no bg, and if i paste It outside it just doesnt work at all and/or doesnt get highlighted like the other commands do when theyre working (i'm using vscode). Also i made sure my bg images were in the right folder and named correctly in the script.
If i dont erase the default bg line It does have a bg when i launch, but its that, the default title bg
They're inside the game folder next to all the other scripts.
title_backgrounds = {
"Title": "gui/Title.png",
"SideA": "gui/SideA.png",
"SideB": "gui/SideB.png",
}
Also I found out that using the jump command anywhere on my script to get the menu to change gives me this error, It's like the label doesn't exist or it's not reading your script :/ (ps: I'm separating the chapters into different scripts, that's why it says chapter1 and not scripts)
While running game code:
File "game/Chapter1.rpy", line 3, in script
jump SideA
renpy.script.LabelNotFound: could not find label 'SideA'.
-- Full Traceback ------------------------------------------------------------
Traceback (most recent call last):
File "game/Chapter1.rpy", line 3, in script
jump SideA
File "renpy/ast.py", line 1938, in execute
rv = renpy.game.script.lookup(target)
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
File "renpy/script.py", line 1217, in lookup
raise LabelNotFound(original)
renpy.script.LabelNotFound: could not find label 'SideA'.