Reported via the Google Web Search Help forum, a user was looking for Pirelli tires and noticed that even though his image search settings was set to the strictest form of SafeSearch, tons of pornographic images were showing up.
Normally when you see a post like this, it is due to the browser having malware on it. But in this case, I was able to replicate it.
Searching for [Pirelli] in Google and setting image search to strict shows me this:
Jay David from Google responded to the complaint saying:
The images are still there.
Forum discussion at Google Web Search Help.