We can change opacity of background elements and even apply filters to them in SVG (filters currently don't work in Safari and IE9).
SVG:
<?xml version="1.0" encoding="utf-8"?>
<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="250px" height="184px" xml:space="preserve">
<defs>
<filter id="f" x="0" y="0">
<feGaussianBlur in="SourceGraphic" stdDeviation="8" />
</filter>
<image id="image" xlink:href="../img/paul.png" x="0" y="0" width="200" height="182" />
</defs>
<use xlink:href="#image" filter="url(#f)" width="200" height="182" x="100" y="130" opacity="0.7" transform="scale(0.8 0.8)"/>
<use xlink:href="#image" filter="url(#f)" width="200" height="182" x="100" y="-100" opacity="0.7" transform="scale(0.8 0.8)"/>
<use xlink:href="#image" width="200" height="182" x="-50" y="0"/>
<use xlink:href="#image" width="200" height="182" x="200" y="0"/>
</svg>