SOURCE

<div class="container">
    <div class="inner">
        <div class="content">
            <img src="https://picsum.photos/200" alt="">
        </div>
    </div>
</div>

.container {
    width: 100%;
    /* height: 100vh; */
    border: 1px solid red;
    /* background-color: red */
}

.inner {
    /* background-color: blue; */
    width: 100%;
    padding-top: 75%;
    position: relative
}

.content {
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
    height: 100%
}
img {
    width: 100%;
    height: 100%
}