When I want to combine two background images, I can simply separate them by comma, e.g.:
.foo {
background-image: url(bg_1.jpg), url(bg_2.jpg);
background-position: center center, left top;
background-repeat: no-repeat, repeat;
}
etc.
What I want to do is to overlay a background image with a color (e.g. rgba(0,0,0,.5)) without having to create a separate layer, using pseudo elements or png images. I thought maybe css gradients may come handy?