CSS Issues with Internet explorer: Background image not shown properly

I’m using a background image as post separator in my child theme using css piece like this:
.hentry {
clear: both;
background-image:url(http:/…/postdiv.png);
background-position:50% 100%;
background-repeat:no-repeat no-repeat;
margin: 0 0 1em;
padding: 0 0 4em;
}

It works fine on chrome. However, IE breaks all over showing the image a thousand times all over instead of just once at the end of the post like a post divider.
How do I fix the appearance of the image to be only at the end of the post to act as a separator in IE?