Featured image as background-image property

How To
1

Is it possible in the post template, in the CSS code to embed a link to a featured image? Like this:

.some_class {
  background-image: url(_featured_image_from_current_post_);
}
2

I usually prefer to do the same effect with an Image element positioned absolute in a parent that is positioned relative (and possible overflow to hidden for parent). It’s same as background-image and you have even better control.

Alternatively you could print the css code to WP head with a filter and then use this class, something like this added to functions.php or through Code Snippets Plugin:

function prefix_add_featured_image_background_style() {
    if (is_singular() && has_post_thumbnail()) { 
        $featured_image_url = get_the_post_thumbnail_url();
        if ($featured_image_url) {
            echo "<style>
                .some_class {
                    background-image: url('{$featured_image_url}');
                }
            </style>";
        }
    }
}
add_action('wp_head', 'prefix_add_featured_image_background_style');