UaMV for now I've whitelisted a few mime types, just to make sure we're not allowing php files. Among them are video, image and audio. As pdf for instance are application/pdf mime types, I'll be allowing you to specify the whitelist yourself.
hcarpach so yes the uploader works, it auto generates a markdown string. In case of images it also generates a previewable markdown string. Also I prefer you to install this extension for now, if you can miss out on the adapters implemented in the image upload extension (imgur for instance). I'll be adding more adapters soon, but I'm not sure the image-only ones will have priority. Feel free to request any missing adapter (upload cloud/platform) by creating an issue.