Isn't this just adding fuel to the fire, by making more people aware of the photo - and thus driving traffic to the site that posted it. That increased traffic will mean the site will maintain a high ranking in Google's search results. I am sure Google could have thought of a better solution - like programing their search engine to produce a disclaimer on the page when the result comes up. That way only people who already had done the search would be made aware of it.
Google has purchased online ads in an effort to explain to users why an offensive image of Michelle Obama is appearing, and is ranked so highly, in its Google Image search results.