make image maintain original ratio css code example

Example 1: preserve aspect ratio image css

/* Simply add width without height,
aspect ratio will be maintained 
and height will be calculated accordingly*/

img {
  width: 100px;
}

Example 2: css keep aspect ratio image

.image-full {
    background: url(...some image...) no-repeat;
    background-size: cover;
    background-position: center center;
}