    /*
     * Method which inserts a full background-image property for a theme image.
     * It checks if the file exists and if it doesn't, it'll throw an error.
     * By default it will not include the background-image property if it is not found,
     * but this can be changed by changing the default value of $include-missing-images to
     * be true.
     */
    @function theme-background-image($path, $extension: $image-extension, $nocheck: false) {
        $path: file_join($relative-image-path-for-uis, $path + '.' + $extension);
        $background-image: none;

        @if $path {
            @if $nocheck {
                $background-image: $path;
            } @else if theme_image_exists($image-search-path, $path) {
                $background-image: $path;
            } @else {
                @warn "@theme-background-image: Theme image not found: #{$path}";
                @if $include-missing-images {
                    $background-image: $path;
                }
            }

            @if $background-image != none {
                $background-image: url(file_join($theme-resource-path, $path));
            }
        } @else {
            @warn "@theme-background-image: No arguments passed";
        }

        @return $background-image;
    }