As I write articles on my own instance of ghost, sometimes I drag and drop multiple instances of the same image because the size doesn’t work for the page. At times I would drop in a screenshot from a desktop or a tablet and it would fill the whole page in a post. What I would do then is resize the picture on the desktop and re-upload the same image again just smaller or bigger, so the old picture wouldn’t get to be used and just stay there in the contents folder for nothing.
I suppose an image-is-used-in-the-post would be cool to add in. Then you’d only keep the images in the
contents/ folder that are actually used in an article. So say when you save the post it would remember that you added an image but it’s not in the article so just delete it. Why would you keep old pictures that are not used?
An even better idea would be to add some kind of an image gallery to see what kind of content you have already with a flag showing if it’s used in a post and give the admin an option to remove it from the gallery. We’d be able to save some substantial amount of space on backups.