.description
{
  display: block;
  width: 200px;
  margin: auto;
  height: 400px;
  overflow: hidden;
}
.description_contenu
{
  position: absolute;
  width: 200px;
  height: 400px;
  overflow: 400px;
  background-color: #EFE9DD;
  font-size: 11.5px;
  font-family:'Georgia';
  color: #3E352E;
  text-align: justify;
  padding:0px;
  opacity: 0;
  -moz-opacity: 0;
  -khtml-opacity: 0;
  filter: alpha(opacity=0);
  transform: all;
-moz-transform: all;
-o-transform: all;
-htm-transform: all;
-webkit-transform: all;
transition: 1s;
-moz-transition: 1s;
-o-transition: 1s;
-htm-transition: 1s;
-webkit-transition: 1s;
}
.description_contenu:hover
{
  opacity: 0.8;
  -moz-opacity: 0.8;
  -khtml-opacity: 0.8;
  filter: alpha(opacity=80);
  transform: all;
-moz-transform: all;
-o-transform: all;
-htm-transform: all;
-webkit-transform: all;
transition: 1s;
-moz-transition: 1s;
-o-transition: 1s;
-htm-transition: 1s;
-webkit-transition: 1s;
}

<div class="description"><div style="display: block; text-align: justify; width: 200px; height: 400px; background: url(http://i.imgur.com/bDu6963.png) center center no-repeat;"><div class="description_contenu"><div style="OVERFLOW: auto; width: 190px; height: 390px; padding: 5px;">Contenu ici - Contenu ici - Contenu ici - Contenu ici - Contenu ici - Contenu ici - Contenu ici - Contenu ici.</div></div></div></div>