Images preloading

index.html

<script>
    window.addEventListener('load', function () {
        const imagesToPreload = [
            '/images/test.png',
            // ..
        ];
        
        let images = [];
        for (let i = 0; i < imagesToPreload.length; i++) {
            images[i] = new Image();
            images[i].src = imagesToPreload[i];
        }
    });
</script>