.cs-logo a {
   background-image: url("/wp-content/uploads/2016/04/dm_logo.png");
}

@media only screen and (min-width: 581px) {

#secondary-menu > ul > li {
   background-image: url("/wp-content/uploads/2014/04/DM-website-04-12-new-layout.png");
}}

@media only screen and (max-width: 580px) {

#secondary-menu > ul > li {

background-image: url("/wp-content/uploads/2014/06/mobile-menu.png");

}}