a.annotation {
  position: absolute;
  border: 3px solid black;
  padding: 0;
  margin: 0;
  display: none;
  cursor: pointer;
}
a.annotation span {
  display: block;
  background: transparent;
  width: 100%;
  height: 100%;
  opacity: 0.3;
  padding: 0;
  margin: 0;
  -moz-opacity: 0.3;
  filter:alpha(opacity=30);
  cursor: pointer;
}
a.annotation:hover { border-color: yellow; }
img.annotated { border-width: 0; }