Edit in JSFiddle

<img id="svg-filter-blur" src="http://css-plus.com/examples/2012/03/gaussian-blur/i/fence.jpg" alt="HTML element blur via SVG" height="200" width="300" />

<svg id="svg-image-blur">
    <filter id="blur-effect-1">
        <feGaussianBlur stdDeviation="1" />
    </filter>
    <filter id="blur-effect-2">
        <feGaussianBlur stdDeviation="2" />
    </filter>
</svg>

#svg-filter-blur { filter:url(#blur-effect-1); margin: 15px; }
#svg-filter-blur:hover { filter:url(#blur-effect-2); }