How to integrate dropzone.js with a specific input field for images?

I am using a form in wordpress that allows users to post a post with images. To create the form I used Frontend Uploader (http://ift.tt/1g6NvZO ).

It uses a specific input field for images:

<input id="ug_photo" type="file" value="" name="files[]" class="" multiple="multiple">

And I'd like to create a dropzone for images with dropzone.js that replaces this input field but is still able to upload the images in the same way. However I'm not sure what I have to tweak to dropzone to make this possible... I tried several other solutions that allowed me to add the images to my original form, but upon submitting I get an error from front-end uploader.

via Chebli Mohamed