For making my movie quiz free of cheaters (at least most of them), I tried to fool Google Images reverse search by adding some noise like described here, on my

For making my movie quiz free of cheaters (at least most of them), I tried to fool Google Images reverse search by adding some noise like described here, on my movie snapshots. Unfortunately it didn't work. The only trick which works the most is to revert horizontally the image, at random. When it works, Google is not about to find similar images.