Spammers are always looking for ways to get their content in front of Google's searchers. When spammers try to promote their pornography, it makes it a bit more upsetting. Because when they do so, it leads to a tremendous amount of porn in Google for a single search term.
In the past week or two, I've seen a large uptick in reports of pornography in both Google Image search and video search. Google has a utility to report offensive images the only issue with that, when a spammer gets their images in the results, it can be somewhat overwhelming and take hours to report all the porn or offensive images.
Jeff from Google said in a Google Web Search Help thread that in those cases, it is best to report mass abuse of pornography in the Google forums instead of using the report offensive image feature. Jeff said:
Thanks for the feedback. I wanted to suggest the "Report Offensive Images" link as an additional option for users. I agree, however, that it can be a bit cumbersome for a query such as [IGA]. In that case, the best option is to report it here in the forum so that myself or someone else on my team can quickly look into the matter.
Do not search for [iga] in Google Image search if you do not want to see pornography.
A bigger issue is a report that went unanswered about video porn. I tried to click the "Report offensive videos" link at the bottom of the results but that link doesn't even work in Google's own browser, Chrome.
In any event, if you do find mass amounts of offensive images, take it to the Google forums.
Forum discussion at Google Web Search Help.
