<actions>
    <group name="images">
        <action contenttype="IMG" type="getvalue" fieldname="width" value="//generalproperties/property[@name='width']" />
        <action contenttype="IMG" fieldname="height" value="//generalproperties/property[@name='height']" />
        <action contenttype="IMG" fieldname="filesize" value="//generalproperties/property[@name='size']" />
    </group>
    <!-- optionally other groups -->
</actions>