JSFiddle - React, Tailwind, and code Playground

HTML

<div class="clip-wrap">
  <img src="https://p6.zdassets.com/hc/theme_assets/184659/200004949/homepage-hero-desktop.jpg" alt="demo-clip-css" class="elem"></div>

CSS

img {
        max-width: 100%;
        height: auto;
        display: block;
    }
    
.clip-wrap {
   position: relative;
}

.clip-wrap:after {
   content: "";
   display: block;
   position: absolute;
   width: 100%;
   bottom: 0;
   left: 0;
   pointer-events: none;
   z-index: 1;
   background: url(data:image/svg+xml;charset=utf-8;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxMDAiIGhlaWdodD0iMTAwIiB2aWV3Qm94PSIwIDAgMTAwIDEwMCIgcHJlc2VydmVBc3BlY3RSYXRpbz0ibm9uZSI+DQogICA8cGF0aCBmaWxsPSIjZmZmIiBmaWxsLXJ1bGU9ImV2ZW5vZGQiIGQ9Ik0wIDAgTDEwMCAxMDAgSDB6Ii8+DQo8L3N2Zz4=); /* Use a white triangle here */
   height: 100px; /* Set this as appropriate */
   background-size: 100% 100%;
}