Как задать два background?

* { 
  margin: 0; 
} 
 
body { 
  height: 100vh; 
  background: #000; 
  position: relative; 
} 
 
body:after { 
  content: ''; 
  position: absolute; 
  top: 0; 
  right: 0; 
  width: 50%; 
  height: 100%; 
  background: url(http://mediad.publicbroadcasting.net/p/kalw/files/styles/medium/public/201601/Nature-Brain.jpg) no-repeat center top; 
  background-size: cover; 
}

* { 
  margin: 0; 
  padding: 0; 
} 
 
body { 
  width: 100vw; 
  height: 100vh; 
  background-image: linear-gradient(90deg, black 50%, transparent 50%), url(https://massaget.kz/userdata/uploads/u61377/1415712179_l.jpg); 
  background-size: cover; 
}