Ah I have now found out why I have only been able to retrieve such a poor image. In fact I am quite pleased that I have managed to get any image at all.
When you go to http://www.google.com/patents
Look at an image, right clear to try to save it. But all images appear as cleardot.GIF. The image can't be saved as this 2kb blank image sits on top of the jpeg underneath to hide it.
I don't know when this started, but must be fairly recent. It is not known why google do this to even things without copyright in the public domain.
To get the image that I did was to download it as a pdf, then save the image as a bitmap then convert it to a jpeg. But does anyone know a cleaner way of doing it to get a decent image?