JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.2.1.js"></script>
<script src="https://rawgit.com/maciej-gurban/responsive-bootstrap-toolkit/master/dist/bootstrap-toolkit.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<div class="row">
  <div class="col-md-4 col-xs-12">
    <figure class="overlay">
      <img src="https://preview.ibb.co/iFKqGk/base.jpg" alt="cat" class="img-fluid">
      <figcaption>Até<br>
        50%<br>
      </figcaption>
    </figure>
  </div>
  <div class="col-md-4 col-xs-12">
    <figure class="overlay">
      <img src="https://preview.ibb.co/iFKqGk/base.jpg" alt="cat" class="img-fluid">
      <figcaption>Até<br>
        30%<br>
      </figcaption>
    </figure>
  </div>
  <div class="col-md-4 col-xs-12">
    <figure class="overlay">
      <img src="https://preview.ibb.co/iFKqGk/base.jpg" alt="cat" class="img-fluid">
      <figcaption>Até<br>
        15%<br>
      </figcaption>
    </figure>
  </div>
</div>

CSS

figure.overlay {
    position: relative;
    width: 100%;
    z-index: 1;
  }
  figure.overlay img {width: 100% }

  figure.overlay figcaption {
    position: absolute;
    z-index: 1000;
    height: 100%;
    width: 100%;
    top: 0;
    /**optional background overlay**/
    background: rgba(255,255,255,0.2);
    /**text, adjust all values as desired**/
    padding: 44% 2% 0 15%;
    font-weight: 700;
    color: purple;
    /**some fallback value**/
    font-size: 16px;
    /**responsive size is roughly 3.4%  of the device's viewport width**/
    font-size: 2.0vw;
  }

JavaScript

(function($, document, window, viewport){
      function setTextSize() {
        if ((viewport.current() == 'xs') || (viewport.current() == 'sm')) {
          $("figure.overlay figcaption").css('font-size','7.0vw');
        } else {
          $("figure.overlay figcaption").css('font-size','2.4vw');
        }
      }

      // Executes once whole document has been loaded
      $(document).ready(function() {
        console.log('Current breakpoint:', viewport.current());
        setTextSize();
      });

      $(window).resize(
        viewport.changed(function(){
          console.log('Current breakpoint:', viewport.current());
          setTextSize();
        })
      );
    })(jQuery, document, window, ResponsiveBootstrapToolkit);