public String[] getPropertyNames() {
        String[] names = new String[properties.size()];
//        int index = 0;
//
//        Enumeration e = properties.keys();
//        while (e.hasMoreElements()) {
//            String name = (String)e.nextElement();
//            names[index++] = name;
//        }
        properties.keySet().toArray( names );
        return names;
    }
Returns a list of the properties recognized by this image.  If
no properties are available, an empty String[] will be returned.

@return an array of <code>String</code>s representing valid
        property names.
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/util/SimpleRenderedImage.java