itch.io

Also there is a file called arrows.json

If you open it, you'll see something like this.

{
    "spriteWidth": 110,
    "spriteHeight": 112,
    "spriteMargin": 0,
    "spriteCount": 8
}

spriteWidth and spriteHeight is how big each note arrow image is. So if you want to change your image size, change those two numbers.