Nowadays, it is possible to do it simply with CSS property "background-blend-mode".
<div id="content">Only one div needed</div>
div#content {
background-image: url(my_image.png);
background-color: rgba(255,255,255,0.6);
background-blend-mode: lighten;
/* You may add things like width, height, background-size... */
}
It will blend the background-color (which is white, 0.6 opacity) into the background image. Learn more here (W3S).