.thumbnail:hover{
background-color: transparent;
}

.thumbnail:hover img{
border: 1px solid blue;
}

.thumbnail span{ /*CSS for text box */
position: absolute;
background-color: lightyellow;
padding: 2px;
left: -1000px;
border: 1px dashed gray;
visibility: hidden;
color: black;
text-decoration: none;
width: 400px;
text-align: justify;
}

.thumbnail span img{ /*CSS for text box */
border-width: 0;
padding: 1px;
}

.thumbnail:hover span{ /*CSS for text box */
visibility: visible;
top: 300px; /*position where text box should offset vertically */
left: 300px; /*position where text box should offset horizontally */
z-index: 50;
}