Django form wizard does not remember file uploaded using jasny

Question

I have included Jasny fileupload component on an existing form part of a wizard.

Everything is working well on the form itself. The trouble is that when navigating to the next form of the wizard, then going back the file uploaded by the user disappeared.

The problem is therefore that if the user is going backwards in the form, he has to reload each time the file that have been uploaded.

Am I doing anything wrong ? The part of the template storing the file is provided below :

<div class="fileupload fileupload-new" data-provides="fileupload">
  <div class="fileupload-new thumbnail" style="width: 100px; height: 100px;"><img src="http://www.placehold.it/100x100/EFEFEF/AAAAAA" /></div>
  <div class="fileupload-preview fileupload-exists thumbnail" style="width: 100px; height: 100px;"></div>
  <span class="btn btn-file"><span class="fileupload-new">Select image</span><span class="fileupload-exists">Change</span>
  {{ form.file_img1 }}
  <a href="#" class="btn fileupload-exists" data-dismiss="fileupload">Remove</a>
</div>

<div class="fileupload fileupload-new" data-provides="fileupload">
  <div class="fileupload-new thumbnail" style="width: 100px; height: 100px;"><img src="http://www.placehold.it/100x100/EFEFEF/AAAAAA" /></div>
  <div class="fileupload-preview fileupload-exists thumbnail" style="width: 100px; height: 100px;"></div>
  <span class="btn btn-file"><span class="fileupload-new">Select image</span><span class="fileupload-exists">Change</span>
  {{ form.file_img2 }}
  <a href="#" class="btn fileupload-exists" data-dismiss="fileupload">Remove</a>
</div>