Random background image (possibly from a list) in color section

i did that here on the page : page-id-34024
https://webers-testseite.de/bg-scheduling/
the color-section has a bg-image ( this is not so important – but style the outlook with that image first ( contain; cover; repeat etc. pp)
This color-section has a custom-class: bg-scheduled
you see that the bg image is then taken from a source folder.
But this is scheduled per day with a fixed image for each weekday – but you see how you can do it. Hope you can transfer this to a randomized order. – i will have a look too.

function schedule_bg_image() {
if(is_page(34024)){ 
?>
<script type="text/javascript">
  var imglocation = "/wp-content/uploads/";
  function ImageArray (n) {
     this.length = n;
     for (var i =1; i <= n; i++) {
       this[i] = ' '
     }
  }	
	image = new ImageArray(7);
	image[0] = 'o2-7.jpg'; // Sunday
	image[1] = 'o2-1.jpg'; // Monday
	image[2] = 'o2-2.jpg'; // Tuesday
	image[3] = 'o2-3.jpg'; // Wednesday
	image[4] = 'o2-4.jpg'; // Thursday
	image[5] = 'o2-5.jpg'; // Friday
	image[6] = 'o2-6.jpg'; // Saturday
	var currentdate = new Date();
	var imagenumber = currentdate.getDay();
	document.getElementById('av_section_1').style.backgroundImage = 'url(' + imglocation + image[imagenumber] + ')';
	
</script>
<?php
}
}
add_action( 'wp_footer', 'schedule_bg_image' );

…and I am sorry to say that it is not working for me as well :-(

Here is the code I’ve customized (the ID of my page is the one below, I’ve double checked it).

function randomize_bg_image() {
if(is_page(11318)){ 
?>
<script type="text/javascript">
(function($){
	    var images = ['img(1).jpg','img(2).jpg','img(3).jpg','img(4).jpg','img(5).jpg','img(6).jpg','img(7).jpg','img(8).jpg'];
	    $('#randomized').css({
	    	'background-image': 'url(/wp-content/uploads/sfondimobile/' + images[Math.floor(Math.random() * images.length)] + ')'
	    });
})(jQuery);
</script>
<?php
}
}
add_action( 'wp_footer', 'randomize_bg_image' );

Images are here:
https://imgur.com/a/tu7Qy05
let me highlight that I’ve copied the images DIRECTLY TO THE FTP SITE, I did not use the Media Library… can this be the reason?

#randomized is correctly set:

https://imgur.com/ELYntMF

But when you open my website in mobile mode, the background is frozen to the original one:

https://www.sentierigressoney.it

@Guenni007, I hope you’ll find some time to give my some hints :)

oh wow – long time ago
ps on that given example page there are both versions – on top : showing the bg-image of that weekday
on bottom randomized.

by the way: here it is for the seasons:

function scheduling_per_season(){
if(is_page(39621)){
?>
<script>
  var currentTime = new Date();
  var month = currentTime.getMonth() + 1;
  var imglocation = "/wp-content/uploads/season-images/";  // put the images in this folder

	switch(true) {
		case (month >= 6 && month <= 8):
			var seasonImg = "summer.jpg";
			var season = "summer";
			break;
		case (month >= 9 && month <= 11):
			var seasonImg = "fall.jpg";
			var season = "fall";	  
			break;
		case (month == 12 || month == 1 || month == 2):
			var seasonImg = "winter.jpg";
			var season = "winter";
			break;
		default:
			var seasonImg = "spring.jpg";
			var season = "spring";
	}
  	document.getElementById('changed_on_season').style.backgroundImage = 'url(' + imglocation + seasonImg + ')';
	document.body.classList.add(season);
	document.getElementById('changed_on_season').getElementsByClassName("av-special-heading-tag")[0].textContent = "It is "+season+""; 
	
</script>
<?php
}
}
add_action('wp_footer', 'scheduling_per_season');

see: https://webers-testseite.de/season-scheduling/