#first-slider .slide1 {
    background-image: url(http://s20.postimg.org/h50tgcuz1/image.jpg);
      background-size: cover;
    background-repeat: no-repeat;
}
#first-slider .slide2 {
  background-image: url(http://s20.postimg.org/uxf8bzlql/image.jpg);
      background-size: cover;
    background-repeat: no-repeat;
}
#first-slider .slide3 {
  background-image: url(http://s20.postimg.org/el56m97f1/image.jpg);
      background-size: cover;
    background-repeat: no-repeat;
}
#first-slider .slide4 {
  background-image: url(http://s20.postimg.org/66pjy66dp/image.jpg);
      background-size: cover;
    background-repeat: no-repeat;
}