how to divide a background image in small blocks while using animejs

I’m trying to create a photo dispersion effect with the help of animejs.

Also, I’ve divided my background image in small blocks by keeping the background position fixed and till now its fine. like this:

But when I include anime js in it, my background doesn’t seems to be a single one. Those all block takes same part of the image like this:

Here is the complete code:

let photoContainer = document.querySelector(".photoContainer")


for(let i = 0; i<100; i++){
    let ele = document.createElement("div");
    ele.classList.add("block");
    photoContainer.appendChild(ele);
}




let block = document.querySelectorAll(".block")
let animation = anime.timeline({
    targets: block,
    easing: "easeInOutExpo",
    loop: true,
    delay: anime.stagger(20, {start:0}),
})

animation
.add({
    delay: 4000,
    scale: 0,
    translateX: function(){return anime.random(-360,2100);},
    translateY: function(){return anime.random(-360,2100);},
    rotate: function(){return anime.random(360,-360);},

    duration : function(){return anime.random(500,3000);}
})
.add({
    scale: 1,
    translateX:0,
    translateY: 0,
    rotate: 0,

    duration : function(){return anime.random(2000,3000);}
})

.photoContainer{
    position: relative;
    display: flex;
    flex-wrap: wrap;
    transform-style: preserve-3d;
    border: 2px solid red;
}

.photoContainer .block{
    position: relative;
    width: 5vh;
    height: 5vh;
    transform-style: preserve-3d;
    perspective: 1000px;
    box-sizing: border-box;
    border: 2px solid green;

    background-image: url(img.png);
    background-color:red ;
    background-size: 50vh 50vh;
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-position: top;
 
}



.dispersionContainer{
    width: 50vh;
    height: 50vh;
    margin: 0px auto;
    /* border-radius:50% ; */
    background-color: black;
    overflow: hidden;
    border: 2px solid red;
}

<body>


    <section id="spanContainer">
            <div class="dispersionContainer">
                <div class="photoContainer"></div>
            </div>

</section>

</body>

Note: When I pushed this code to github previously, it was fine but when I cloned it again this problem arised.

Thanks in advance.