<div class="box"></div>

<script>
if (CSS.paintWorklet) {              CSS.paintWorklet.addModule('/t_afif/pen/f948d37e306e7824171c0007674272e0.js');
}
</script>

@property --f-o{
  syntax: '<number>';
  inherits: false;
  initial-value: 1;
}

.box {
  --r:2/1; /* ratio */
  --d:10s; /* duration */
  --f-n:40;
  --f-m:20;
  -webkit-mask: paint(fragmentation);
          mask: paint(fragmentation);
  max-width:800px;
  aspect-ratio: var(--r);
  background:
     url(https://picsum.photos/id/15/800/400),
     url(https://picsum.photos/id/110/800/400),
     url(https://picsum.photos/id/1014/800/400),
     url(https://picsum.photos/id/305/800/400);
  background-repeat:no-repeat;
  margin:auto;
  animation:
      c var(--d) linear infinite ,
      i calc(var(--d)/8) linear infinite alternate calc(var(--d)/8);
}

@keyframes c {
  0% ,24.9% {background-size:cover,0 0,0 0,0 0}
  25%,49.9% {background-size:0 0,cover,0 0,0 0}
  50%,74.9% {background-size:0 0,0 0,cover,0 0}
  75%,100%  {background-size:0 0,0 0,0 0,cover}
}
@keyframes i {
  0%,15% {--f-o:1}
  100%   {--f-o:0}
}

body {
  background:pink;
}

registerPaint('fragmentation', class  {

  static get inputProperties() {
    return [
      '--f-n',
      '--f-m',
      '--f-o'
    ]
  }
  
  paint(ctx, size, properties) {

    const n = properties.get('--f-n');
    const m = properties.get('--f-m');
    const o = properties.get('--f-o');
    const w = size.width/n;
    const h = size.height/m;
    const l = 10; 
   
    const mask = 0xffffffff;
    const seed = 30;
    let m_w  = (123456789 + seed) & mask;
    let m_z  = (987654321 - seed) & mask;
    let random =  function() {
      m_z = (36969 * (m_z & 65535) + (m_z >>> 16)) & mask;
      m_w = (18000 * (m_w & 65535) + (m_w >>> 16)) & mask;

      var result = ((m_z << 16) + (m_w & 65535)) >>> 0;
      result /= 4294967296;
      return result;
    }
    
    for(var i=0;i<n;i++) {
       for(var j=0;j<m;j++) {
         ctx.fillStyle = 'rgba(0,0,0,'+((random()*(l-1) + 1) - (1-o)*l)+')';
         ctx.fillRect(i*w-.5, j*h-.5, w+.5, h+.5);
        }
      }
  }

})