I just found out that you can directly push drafts from iA Writer to a blog running on Ghost with just one click.

Excited about this fact I followed the short official guide and set everything up. Unfortunately I ran into a problem which took me a bit to resolve: Every time I linked images from my blog post the push to Ghost would fail with a very generic error message:

Failed to upload some images. Received an error when connecting to the service

I figured that it was maybe related to me self-hosting the blog. It's currently running behind nginx so my guess was that something is going wrong with the proxying, caching or other annoying to debug settings.

After testing with a few different sized images I realized it only happens on images that are bigger than 1MB which pointed me to the file upload limit of nginx. After changing it everything worked and so the fix was to set it a bit higher by tweaking the limit via client_max_body_size and reloading nginx.

Example from my configuration

server {
    listen      443;
    server_name blog.notmyhostna.me;
    ...
    client_max_body_size 50M;
    ...
 }   

After doing that I also found that it's something that's being mentioned in the Ghost Docs here.

Hope that's helpful to someone else finding that through a search engine.