To let the background-image fully fill the space that is available you can use background-size: cover;
:
.roundedImage {
background: url(http://placehold.it/50x50);
background-repeat: no-repeat;
background-size: cover;
overflow:hidden;
-webkit-border-radius:50px;
-moz-border-radius:50px;
border-radius:50px;
width:90px;
height:90px;
}
Note that i've added the inline style in the css code.