This is being considered, with the drawback that you either have to do some JavaScript bullshit or use a form for voting (search engine spiders don't submit forms). As a workaround, you could cange the order of your rating buttons (this way the search engine spiders would vote all pics with "5" instead of "0", which of course only fixes things cosmetically).
In the long run we will probably have to go for a form-based voting system together with some JavaScript magic that submits the form on the first click of a rating button.
Joachim