There's a few guro pictures, but people took that as an opportunity to post just guro with random yukkuris in it because "omg it has a yukkuri", similar to hentai with yukkuri overlays. And it's weird coming from a yukkuri site with lots of abuse, but we have a lot of people here that don't actually like guro. As a personal preference I don't like guro (and don't like jissous/fluffies either).
Disregarding the fact that 90% of stories involving guro or massacring of humans are troll-ey in nature, even if you have a story where humans are preyed upon by yukkuris, I don't believe there needs to be guro to tell the story. Human suffering is easily portrayed without gratuitous violence, and you can ask yourself one quick question before deciding if guro is needed:
"does it improve my story?"
As a general rule, guro is not needed (and doesn't add much to a yukkuri story) and therefor disallowed. Even war stories are better told from a desperate struggle perspective instead of "bodies everywhere". Text stories featuring some guro are allowed though.