Urgh, not again. I inadvertently opened a couple of the threads last time and the images (both of women, why am I not surprised?) were absolutely vile.
It seems that whoever is doing it (whether it's all one individual or several) knows that MN doesn't have a full complement of mods at night and instead relies on the Night Watch.
I normally browse a fair bit during the night but I can really do without seeing that sort of shit.