JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div id="seu-elemento">
    ALGUM TEXTO
    </div>
</div>

CSS

#container {
    width: 300px;
    height: 300px;
    background-color: #ffff99;
    background-image: url(http://images.gofreedownload.net/flag-of-brazil-6062.jpg);
}
#seu-elemento {
    z-index: 1;
    position: relative;
    height: 100px;
    text-align: center;
    font-size: 30px;
}

#seu-elemento:before {
    background: url(http://www.featurepics.com/FI/Thumb300/20120202/Colorful-Tile-Wallpaper-2116697.jpg);
    opacity: .6; 
    z-index: -1;
    content: "";
    position: absolute;
    top: 0; 
    left: 0;
    width: 100%; 
    height: 100%;  
}