My file structure for a PyGame project throws countless errors - what am I doing wrong?

Question

I'm working on a project for college, and one of the objectives is to have a functioning and efficient file structure to contain the game. In theory, I completely get this. I've made file structure diagrams and begun coding my modules - but almost everything I do seems to throw an error. Here's a sample of my file structure.

/main folder

    main.py

    /gameloop
        mainGameLoop.py
        /images
            background1.png
            background2.png
        /data


    /sprites
        spriteClasses.py
        /images
            image1.png
            image2.png
        /data
            statsSheet1.txt
        

    /menus
        pauseMenu.py
        startMenu.py
        saveMenu.py
        /images
            image3.png
            image4.png
        /data


    /items
        itemClasses.py
        /images
            image5.png
            image6.png
        /data

main.py calls mainGameLoop.py in /gameloop. However, any entities that have been loaded into mainGameLoop.py (such as background images or fonts) cannot be accessed by main.py, and I get an error.

For example, importing mainGameLoop into main.py and calling a showBackground function from it gives the error: "FileNotFoundError: [Errno 2] No such file or directory: 'background1.png'"

Similarly, I want to be able to call pauseMenu from inside mainGameLoop. What's the best way to do this?