The editor toolbar currently supports bold, italic, headings (H2/H3), block quotes, bullet and numbered lists, links, and inline code — everything you need for a well-structured article.
Images
Direct image embedding in posts is on the roadmap but not live yet. In the meantime, focus on writing that stands on its own — some of InkRoar's highest-performing posts (see the feed's Top rankings) are text-only.
Markdown shortcuts
Typing plain text and separating paragraphs with a blank line is all you need — the editor doesn't require you to learn markdown syntax.