body {
  background: url(bajk.jpg) no-repeat center center fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  text-align: center;
}
body .content-wrapper {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}
body .content-wrapper img {
  border-radius: 30px;
}