css: fit rounded (circle) image (do not stretch it)

I recommend applying the images with background-image to a div and then applying background-size: cover to ensure the ratio stays correct regardless of the image's original size/ratio:

JS Fiddle

HTML

<div class="company-header-avatar" style="background-image: url(https://dl.dropboxusercontent.com/u/59666091/6E06C3D.jpeg)"></div>

<div class="company-header-avatar" style="background-image: url(https://dl.dropboxusercontent.com/u/59666091/8WluhcUlWl8.jpg)"></div>

CSS

.company-header-avatar{
    width: 60px;
    height: 60px;
    -webkit-border-radius: 60px;
    -webkit-background-clip: padding-box;
    -moz-border-radius: 60px;
    -moz-background-clip: padding;
    border-radius: 60px;
    background-clip: padding-box;
    margin: 7px 0 0 5px;
    float: left;
    background-size: cover;
    background-position: center center;
}