The score next to your name is a reputation score. Making a couple comments with threats resulted in your reputation score being lowered from downvotes. Threats are not a socially productive way to get what you want.
You should be able to post, I think its just the image uploader that doesn't work for reputation scores below 10. Use offsite image hosting until your reputation score improves.
RE: Steemit's Malicious @steemcleaners downvote ATTACKS