Before monetizing content on the internet, you should first look if it's your original creation or not. If it is copied from other artists, you should always put the source or if you can, always ask for permission from them.

Technically, you painted it. But you only copied it from an existing artwork by Rahmat Kurniawan and you didn't add any other elements so that doesn't make it an original content.

We at OCD only curate original content.

I suggest you edit your post and credit the artist which you copied this from and do this on your posts from now on. (Do this to your previous posts as well. Like this one.