I think the first step is correcting the things you're doing wrong, such as not removing the potential for your site to be showing photos of graphic anal sex on the front page. I'm a bit surprised you didn't 1> foresee the potential for abuse or inappropriate images and 2> fix it immediately as soon as it was brought to your attention.

Being on the front page of HN is a grand thing. Unfortunately you may be not only squandering this chance for positive results, but bringing yourself negative publicity.