Dropzone.js as a profile photo uploader. How to do it?

I have a form that edits user profile, and I want to do a async profile photo upload. My layout looks like this:

The behaviours I have to have are:

• dropzone should load the current photo from server (done, used mockFile and its working);
• I'd like to disable the drag/drop functionality, but don't know if its possible;
• To change picture, user should click the "change pic" button and dropzone should open "browse..." window, user selects the photo and when click ok dropzone should automatically remove the mockFile, change thumbnail and upload the new picture asynchronously.

Anyone could help me with this?