I don't understand the point of collating those on a tumblr though. I get there is educational value to them (death is never dignified, messed up stuff happens in the world, and that is the reality), but I can't tell if you're just posting it for the shock factor.
As part of Defence & Security studies, I've seen some brutal stuff, like videos of Islamic militant beheadings as carried out by groups like ISIS and al-Nusra. When you think of beheadings, you probably think of the clean 'off with ze head' decapitations, yet nothing could be further from the truth. Blunt carving knives is all I'll say.