<div class="main">
<div class="one-time">
    <div><img src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Monasterio_Khor_Virap%2C_Armenia%2C_2016-10-01%2C_DD_25.jpg/1200px-Monasterio_Khor_Virap%2C_Armenia%2C_2016-10-01%2C_DD_25.jpg" data-cover="1"></div>
    <div><img src="https://www.atlasandboots.com/wp-content/uploads/2019/05/ama-dablam2-most-beautiful-mountains-in-the-world.jpg" data-cover="2"></div>
    <div><img src="https://i.pinimg.com/originals/b8/9a/84/b89a84d316e74a3402ec1c8e7545f1bd.jpg" data-cover="3"></div>
</div>
</div>
<div id="results"></div>

.main {

  padding: 30px;
}
.slick-prev:before, .slick-next:before {    
    font-size: 30px;
    line-height: 1;
    opacity: .75;
    color: black;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
.slick-prev:before {
    content: '←';
}
.slick-next:before {
    content: '→';
}
.slick-prev, .slick-next {
    font-size: 0;
    line-height: 0;
    position: absolute;
    top: 50%;
    display: block;
    width: 20px;
    height: 20px;
    padding: 0;
    -webkit-transform: translate(0, -50%);
    -ms-transform: translate(0, -50%);
    transform: translate(0, -50%);
    cursor: pointer;
    color: transparent;
    border: none;
    outline: none;
    background: transparent;
}
.slick-next {
    right: -25px;
}
.slick-prev {
    left: -30px;
}
.slick-track .slick-slide {
    display: block;
    height: 100%;
    width: 100vw;
}

$('.one-time').slick({
  dots: false,
  infinite: true,
  speed: 300,
  slidesToShow: 1,
  adaptiveHeight: true
});

$('img[data-cover]').each(function(){
  var rParentHeight = $(this).parent().height();  
  $(rParentHeight).each(function(){
  $('#results').append(rParentHeight + '<br />');
    });
});