.se-pre-con {
    position: fixed;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    z-index: 9999;
    background: url(/images/Preloader_3.gif) center no-repeat #fff;
}
.desk-img {
    display: block;
  }
  
  .mobile-img {
    display: none;
  }
  
  @media (max-width: 700px) {
    .desk-img {
      display: none !important;
    }
    .mobile-img {
      display: block;
    }
  }