You shouldn’t even add code to fix it, it is a client side virus. That means it isn’t even on your site and the ads will overlay on everyone’s site, even google image results has the ads if the person has the virus. Adding the code just makes it that much harder to track down the virus to being inside the browser. Its like you have a glowing ball and you put a cover on it with duct-tape.
@ AJaegle: I already solved the issue for people it is a browser extension that hijacks <img> tags.