Another one with an SVG as inline overlay-image (note: if you use #
inside the svg-code you have to urlencode that!):
background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1 1"><path fill="rgba(255, 255, 255, 0.4)" d="M0 0h1v1H0z"/></svg>')
no-repeat center center/cover,
url('overlayed-image.jpg') no-repeat center center/cover;