[css] CSS transition fade on hover

I've encountered a problem with CSS transitions. I'm designing a CSS gallery for my portfolio and I need my images to fade in on hover. I've been playing around with this for over an hour and I was hoping someone could point me into the right direction.

Here is a simplified version to it with JSFiddle

This will do the trick

.gallery-item
{
  opacity:1;
}

.gallery-item:hover
{
  opacity:0;
  transition: opacity .2s ease-out;
  -moz-transition: opacity .2s ease-out;
  -webkit-transition: opacity .2s ease-out;
  -o-transition: opacity .2s ease-out;
}