Chrome cannot scale SVG vertically or horizontally.

For this example we will use:

• Two HTML Tags for images, one without size and the other with a height equal to double width
• A div container with a CSS background-image

<!-- HTML -->
<img id="a" src="http://upload.wikimedia.org/wikipedia/commons/b/b0/NewTux.svg">

<img src="http://upload.wikimedia.org/wikipedia/commons/b/b0/NewTux.svg"width="50px" height="100px">

<div></div>

/* CSS */
#a {
    width: 50px;
    height: 100px;
}

div {
    width: 50px;
    height: 100px;
    background-image: url(http://upload.wikimedia.org/wikipedia/commons/b/b0/NewTux.svg);
    background-size: 50px 100px;
}

If you try the same code in Firefox it will work for the 3 cases, you will see a vertical strech for this example with height equal to double width. So, if you want to keep the same behaviour in all browsers, you should change size proportionally. Edit the SVG itself if you wish some width and/or height deformations.

See a real example: