moonCopy,        //resized image of the image (visible)

    imageRatio;     //ratio of the image h/w    

function preload() {

    moon=loadImage("L_O.jpg", img => moonCopy = img.get());

}

function setup()   {

    createCanvas(windowWidth, windowHeight);

    imageRatio = moon.height/moon.width;

    print("imageRatio: "+imageRatio);

  moonCopy.resize(windowWidth,0);

}

function draw() {

    background(255);

    image(moonCopy,0,0);

}

function windowResized() {

    resizeCanvas(windowWidth, windowHeight);

    print("resizing to: "+windowWidth+" "+windowHeight);

    if (windowWidth < moon.width){

        moonCopy = moon.get();

        moonCopy.resize(windowWidth,0);

    }

}