That's something you can't stop, you just seem to be beating around a solution. I also secondly doubt someone is going to feel desperate enough to raise their ranking for this, so I don't see why your too worried about making an image.
I didn't mean it in a bad way. If it seems really easy for sites to fake, which it does to me, I won't take the rating seriously (on other sites). I think putting the websites URL on the image would not be difficult and would help.
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