define size of image in html for responsive code example

Example 1: responsive img

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

Example 2: Scaling Images and Videos css

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

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