.upload-btn-wrapper {
  position: relative;
  overflow: hidden;
  display: inline-block;
}

.btns {
  border: 2px solid gray;
  color: gray;
  background-color: white;
  padding: 4px 10px;
 
  font-size: 20px;
  font-weight: bold;
}

.upload-btn-wrapper input[type=file] {
  font-size: 100px;
  position: absolute;
  left: 0;
  top: 0;
  opacity: 0;
}

.thumbnail{        
    width: 30%; 
    // or you could use percentage values for responsive layout
    // width : 100%;
   
    overflow: auto;
}


.big-thumbnail {
  width: 50%; 
    // or you could use percentage values for responsive layout
    // width : 100%;
   
    overflow: auto;
}
.thumbnail img{
    // your styles for the image
    width: 100%;
    height: auto;
    display: block;
}

 .edit_hover_class a{
  visibility:hidden;
}
.edit_hover_class:hover a {
 visibility:visible;
}