int19h I see. There's no known issues at the moment - if you for example search for names of popular adult websites or adult actors and you get NSFW content, then it is working properly.
So, that sounds like it could just be relating to the quality of the primary index we are using for images. I would compare a couple queries against Bing and Google, that would probably make the issue more clear.
If that is the case, then there isn't much to do here yet, besdies exploring diversifying our image sources - a much longer term task.