*sigh* Franarok...have you read the posting guidelines? Do so, and tell us what you see. I fear you may have violated one of the posting guidelines, so could you check?
This may come off as rude Byakugan, but perhaps instead of speaking to him as thought he were a child that drew on the wall with crayons, you could simply tell him what he did wrong, not to do it again, and to check the guidelines before posting.
Unless it's damn good. But even so, it'll be frowned upon.
It's a different story if you're such a good artist that your works have been recognized and posted on Danbooru by other members, and one day you did it yourself. Then it's not just okay, it's pretty much an honor for Danbooru. Unless that's the case, refrain from posting your own artwork. To say the very least, Danbooru can't guarantee its approval.