def METHOD_NAME(self):
    """
    <alternatives>
        <graphic xlink:href="original.tif"/>
        <graphic xlink:href="padrao.png" specific-use="scielo-web"/>
        <graphic xlink:href="mini.jpg" specific-use="scielo-web" content-type="scielo-267x140"/>
    </alternatives>
    In the above case, this property returns 'original' for original.tif, 'optimised' for pattern.png and 'thumbnail' for mini.jpg'.
    """
    if "content-type" in self.node.attrib:
        return "thumbnail"
    elif "specific-use" in self.node.attrib:
        return "optimised"
    else:
        return "original"