echo '<li>',
'<a href="' . $slide['slide_url'] . '"><img src="' . get_template_directory_uri() . '/images/transparent.png" style="background: url(' . $slide['slide_image_url'] . ') no-repeat center; background-size: cover;" alt="' . $slide['slide_title']. '" /></a>',

 '<div class="rslides-content">',