This is  interesting.In comparision Christophe Pellier's images look very equally when equally
processed.See attachment.

Left: one of Pellier from 2004
mid: my image from Aug 7 ,2006
Right: same image as mid,but processed using my own method.

Now some may be aware of what I mentioned earlier. Those albedo features are
certainly contrast effect of the bright polar region and the darker disk.You may even
see that the polar region has become 'smaller.'

[Ralf Vandebergh:Neighbourhood of Maastricht Netherlands]