File input in admin forms

Hello,

I’m very interrested by the new file input type added in version 1.3.7
I ask a few question here as I didn’t find the answer in wpmvc.org.

I added this line in my form.
echo $this->form->file_input('cc_resp_picture', array('label' => 'Image', 'class' => 'form-control'));

It shows a file input form and the image name is recorded in the ‘cc_resp_picture’ field of my database. But the file itself seems not to be uploaded. How can I move the uploaded file where I want ?