dragging files into document generates tags

currently when I drag an image into a document, I get the path, which is something. If I drag in a JS or CSS or HTML file, the contents are inserted -- I can imagine cases where you'd want that, but I never do. What I'd love is the ability to configure what happens when I drag in different kinds of files. Surprisingly, I've only seen one editor for Mac that offers this: http://coteditor.github.io

Here's a screenshot: