#img-zoomer-box {
  max-width: 1100px;
  height: auto;
  position: relative;
  margin: 10px auto;
}

#img-1 {
  width: 100%;
  height: auto;
}

#img-zoomer-box:hover, #img-zoomer-box:active {
  cursor: zoom-in;
  display: block;
}

#img-zoomer-box:hover #img-2, #img-zoomer-box:active #img-2 {
  opacity: 1;
}
#img-2 {
  width: 340px;
  height: 340px;
  background: url('http://www.bergeracpropertyservices.com/images/map.jpg') no-repeat #FFF; 
  box-shadow: 0 5px 10px -2px rgba(0,0,0,0.3);
  pointer-events: none;
  position: absolute;
  opacity: 0;
  border: 4px solid whitesmoke;
  z-index: 99;
  border-radius: 100%;
  display: block;
  transition: opacity .2s;
}