JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main_slide_back">
    <img src="http://www.tv-testbild.com/ganzneu/arte.jpg" />
</div>
<div style="height: 500px">Tigerente</div>

CSS

.main_slide_back {
    top: 0px;
    left: 0px;
    margin: -8px 0 0 -8px;
    width: calc(100% + 16px);
    height: 100%;
    z-index: 1;
    position: relative;
}
.main_slide_back:after {
    content:'';
    top: 0;
    left: 0;
    z-index: 2;
    width: 100%;
    height: 100%;
    position: absolute;
    background: #08598D;
    opacity: 0.4;
}
.main_slide_back img {
    width: 100%;
    height: 100%;
}