.gallery {

  width: 600px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center ;
          
  }
 
        

.gallery img {
  
  width: 100px;
  height: 100px;
  object-fit: cover;
  border: 2px solid darkgreen;
  background: yellowgreen;
  margin: 2px;
  
}
  

.gallery img:hover {
  object-fit: contain;
  }
body {
  background-image: url(games/rose.gif) ; }