<?php if(is_single()):
                $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' );
            ?>
                <?php if ( has_post_thumbnail() ) { ?>
                    <div class="featured_image" style="background: url('<?php echo $image[0]; ?>') no-repeat scroll <?php the_field('bg_vert_posisjon'); ?> <?php the_field('bg_hor_posisjon'); ?> / cover; min-height: 700px; position: relative; width: 100%; background-attachment: <?php the_field('bg_oppforsel'); ?>">
                <?php } else { ?>
                <div class="no_feature_image"></div>
                <?php } ?>

background: url('http://skarpsinn.no/wp-content/uploads/2014/04/banner_oeva.png') no-repeat scroll center center / cover

background: url('http://skarpsinn.no/wp-content/uploads/2014/04/banner_oeva.png') no-repeat     scroll center center;
min-height: 700px;
position: relative;
width: 100%;
background-attachment: initial;
background-size: cover;