I would have thought describing images you post to spaces for blind people would be common sense, but do find my self enforcing rules on that all the time. Rules that are front and center. A real code of conduct formalizes rules, allows for consistent enforcement, and informs minority populations of the protections they may expect. If you don’t need that, I’m happy for you, but you may want to explore the nature of that privilege. Whether or not that’s necessary in the context of FOSS projects depends on multiple factors. It’s certainly not necessarily if you want to be a benevolent dictator for life.