Updated Image search settings which uses the same algorithms as in Web search also works now in Google Image Search. With this SafeSearch filter you will be given the warning, “Use the SafeSearch menu to filter explicit results” for the search keyword which might be linked to explicit results. Two options will be given. Check “Filter explicit results” when you are not searching for something sexually explicit. Otherwise, “Filter explicit results” is to be left unchecked.
Read the full article here:
Google Updates SafeSearch Filter In Image Search