Answers for "background image with layer black in css"

add black layer on image css

.card-overlay {
  background:
  linear-gradient(
    rgba(0, 0, 0, 0.5),
    rgba(0, 0, 0, 0.5)
  ),
  url('https://www.placecage.com/c/460/300');
}

html layers over background-images

<div class="background">
    <div class="layer">
    </div>
</div>