This package is based on the popular SimpleMDE markdown editor. The package adds a new property editor to Umbraco which can be used to add markdown and includes a live preview.
The image upload functionality is hooked into Umbraco's media picker so you can choose and upload images directly from/to Umbraco's media library.
Tested on Umbraco 7.6, but as the package is fairly simple it's likely to work on older releases.
If you encounter an issue please raise an issue over at Github.