intro image adjust to screen size html css code example

Example 1: Scaling Images and Videos css

.container {
  width: 50%;
  height: 200px;
  overflow: hidden;
}

.container img {
  max-width: 100%;
  height: auto;
  display: block;
}

Example 2: how to set background automatically with my screen height

html { 
  background: url(image.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
     -moz-background-size: cover;
       -o-background-size: cover;
          background-size: cover;
}