dropzone example

Just use :

$(".dropzone").dropzone.removeAllFiles(true);

Select allOpen in new window

So, for example, with a button :

<button onclick="removeMyFiles()">remove files</button>
<script>
var removeMyFiles = function() {
      $(".dropzone").dropzone.removeAllFiles(true);
}
</script>

Select allOpen in new window

The drop zone inside of div has each upload picture and when the picture is mouse over, it shows [x]
And i hope I can make deleting the picture by a click on image

I don't think your solution work

I will call ajax/Jquery to get something done with the server side. so you do not have to worry about server call.

In that case, refer to my answer in other post

<script src="dropzone.js"></script>
<div class="submit-section">

    <form action="/Home/Upload/" class="dropzone" id="myAwesomeDropzone"></form>
</div>

<script>
    Dropzone.options.myAwesomeDropzone = {
        init: function () {
            this.on("removedfile", function (file) {
                alert("CODE of the AJAX function to delete file from server.");
            });
        }
    };
</script>

Select allOpen in new window

it shows [x]

The "X" you're seeing is an icon when it fail to upload, not a button to remove the picture
 
If you really want to use one of these "icon" to remove :

$(".dz-success-mark,.dz-error-mark").click(function() { // success or error
     $(".dropzone").dropzone.removeAllFiles(true);
});

Select allOpen in new window