title: How to use addedfile event listener of dropzone.js to add an element to the preview?
body: <p>I'd like to append a radio button for each preview element like a default or primary photo function. How can I do it without touching the dropzone.js code and how to post the dropzone form even if there's no newly uploaded file, e.g. the dropzone form is showing files from server and I only want to tick a default picture.</p>