There was nothing risque in my thumbnail, I was careful to avoid that. But I have just come from seeing quite a few gallery thumbnails that I'm fairly sure were not automatically generated and they do show nekkid female boobs. Which, don't get me wrong, I do not object to under most circumstances. The "Sparkle" thumbnail only showed a section of torso and arm, not even a bare male nipple. And it did meet the "must be cropped from the original image" requirement -- I've the layered .psd file to prove it. No idea what got it bounced, maybe in future I won't bother with making thumbnails either, though I do hate spoilers.