The standard Ghost admin interface works quite well on mobile devices. I can do blog configurations, edit, create and delete articles. Everything looks good and works reliable. Everything, except image upload, which is not implemented yet, so you need to go the indirect way via PC.
Ghostly is a native iOS App which works with Ghost.org hosted, aswell as self-hosted Ghost blogs. It even allows moderation of Disqus comments!
Native Image Upload
Here is the added value in contrast to the webapp: it allows a native image upload. Take a picture, open Ghostly, upload, publish, done. Just as I like it!
A second handy feature is the connection to Disqus. Once authorized via Disqus I can moderate all comments. No need for the Webinterface. Perfect!
Ghostly allows to store credentials of multiple Ghost installations. Afterwards I can switch comfortably between those accounts.
In my opinion the app is with 2.99 € quite over the top. Sure, image upload and Disqus integration are two handy features. But except those it doesn't offer much more value than the webapp. Also the UI is still a bit stuttering, sometimes the Disqus part doesn't work as expected and the app resolution isn't yet compatible to current generation iPhones.
Nevertheless: currently Ghostly is the only way to publish your images on mobile devices. Therefore the price is somehow legit. Mobile upload of official Ghost is a "planned feature". By now I couldn't find any GitHub Issues regarding a final implementation.
Let's hope Ghostly will also support future versions of Ghost and doesn't end up as a hobby project.