how to make all images same size in css code example

Example 1: make images same size css

img {
    float: left;
    width:  100px;
    height: 100px;
    object-fit: cover;
}

Example 2: product list fix height image css

<div class="container">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
    <img width="400" height="400" src="http://i.stack.imgur.com/aEEkn.png">
</div>