@media (max-width: 768px) {
  .bg-image_page {
    background-image: url( "../images/bg_image_sp.jpg"); 
    background-size: cover;
  }
    

    
    
}
@media (min-width: 768px) {
  .bg-image_page {
    background:url("../images/bg_image.jpg") center no-repeat;
    background-size: cover;
  }
    
    
}