[sasvari]

  vim + git + markdown

This, actually using vimwiki, is my setup for both my private knowledge management/kind of diary system and my lab notebook at work for quite some time now. Works flawlessly. See [0] for a pretty nice setup.

Doesn't solve your image issue, but for text-only it's a pretty nice solution if you're comfortably living in vim anyway.

[0] https://news.ycombinator.com/item?id=4822796

[sciencerobot]

Thanks. I'm doing something similar with Gollum [0].

[0] https://github.com/gollum/gollum