power-six/styles.css

* {
   margin: 0;
   padding: 0;
   box-sizing: border-box;
}

html, body, .square, img{
   height: 100%;
}

.row {
   height: 12.5%;
}

.square {
   width: 12.5%;
   float: left;
}

img{
    width: 100%;
    object-fit: contain;
}