Why don't you try this fiddle I made?
The idea is to use the background-size: cover;
CSS property which handles the centering, cropping and, well, covering. Here's an extract from the fiddle:
div.yourWrapper {
width: 50px;
height: 50px;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
background: url('some_image.jpg') no-repeat center center;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
I have no idea how this downgrades in IE and seriously, supporting Opera is just wrong due to extremely low market adoption (but that's my personal opinion, you can start yelling at me now).