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


    .thumb img { 
      filter: none; /* IE6-9 */ 
      -webkit-filter: grayscale(0); 
      border-radius:5px; 
      background-color: #fff; 
      border: 1px solid #ddd; 
      padding:5px; 
    } 
    .thumb img:hover { 
      filter: gray; /* IE6-9 */ 
      -webkit-filter: grayscale(1); 
    } 
    .thumb { 
      padding:5px; 
    }