User:Nano/common.css

.hover-image {
  position: relative;
  display: inline-block;
}

.hover-image .tooltip-image {
  display: none;
  position: absolute;
  top: 10px;
  left: 110%;
  z-index: 10;
  background: white;
  padding: 5px;
  border: 1px solid #ccc;
}

.hover-image:hover .tooltip-image {
  display: block;
}