.thumbnail_pic_wall{

 position: relative;
 z-index: 0;

}

.thumbnail_pic_wall:hover{

 background-color: transparent;
 z-index: 50;

}

.thumbnail_pic_wall span{

 position: absolute;
 background-color: #ebf0f1;
 padding: 5px;
 left: -1000px;
 border: 1px dashed gray;
 visibility: hidden;
 color: black;
 text-decoration: none;

}

.thumbnail_pic_wall span img{ 

 border-width: 0; 
 padding: 2px;

}

.thumbnail_pic_wall:hover span{ 
 
 visibility: visible;
 top: 0;
 left: 0px; 
 top: 20px; 
}

.thumbnail_wall{

 position: relative;
 z-index: 0;

}

.thumbnail_wall:hover{

 background-color: transparent;
 z-index: 50;

}

.thumbnail_wall span{

 position: absolute;
 background-color: #ebf0f1;
 padding: 5px;
 left: -1000px;
 border: 1px dashed gray;
 visibility: hidden;
 color: black;
 text-decoration: none;

}

.thumbnail_wall span img{ 

 border-width: 0; 
 padding: 2px;

}

.thumbnail_wall:hover span{ 
 
 visibility: visible;
 top: -25;
 left: 10px;

}