This is evidently a change forced on US users only by Google. They have removed the ability to turn SafeSearch off with an image search, and are saying that to get the same results, you need to be very specific. So why only the US?
http://www.webpronews.com/google-preventing-u-s-users-from-disabling-safesearch-2012-12
However, there is a workaround for now. Simply go to Google UK which is:
and all the options to adjust search filters are still there whether you are signed in or not. Not sure why they think only US users need a nanny....
