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<!-- Nowadays, it is possible to do it simply
with CSS property "background-blend-mode"
and combining it with background-color -->
<div id="content">Only one div needed</div>
<style>
div#content {
background-image: url(my_image.png);
/* For Light Image */
background-color: rgba(255,255,255,0.6);
/* For Dark Image */
background-color: rgba(0,0,0,0.6);
background-blend-mode: lighten;
/* You may add things like width, height, background-size... */
}
</style>