<FeatureTypeStyle>
    <Rule>
        <PointSymbolizer>
            <Graphic>
                <ExternalGraphic>
                    <OnlineResource xlink:type="simple" xlink:href="smileyface.svg" />
                    <Format>image/svg</Format>
                </ExternalGraphic>
                <Size>32</Size>
            </Graphic>
        </PointSymbolizer>
    </Rule>
</FeatureTypeStyle>