Django UploadFile

gistfile1.py

def upload_to_valid_name(prefix_dir):
    ''' Create the right function '''

    def get_valid_name(instance, name):
        from django.template.defaultfilters import slugify
        from django.utils.encoding import smart_str
        import os
        n = name.rsplit('.',1)[0]
        ext = name.rsplit('.',1)[1]
        n = smart_str(slugify(n).replace('-', '_'))
        return os.path.join(prefix_dir, '%s.%s' % (n, ext))

    return get_valid_name

class Firm(models.Model):
    name         = models.CharField(_(u'name'), max_length=50,
                                    help_text=_(u"Champ obligatoire."))
    image        = models.ImageField(_(u'logo'), 
                                     upload_to=upload_to_valid_name('uploads/logo'), 
                                     null=True, blank=True))



@login_required
def firm(request, firm_id):
    firm = get_object_or_404(Firm, pk=firm_id)

    if request.method == 'POST':
        form = FirmForm(request.POST, request.FILES, instance=firm)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('/')
    else:
        form = FirmForm(instance=firm)

    return render_to_response('firm/form.html',
                              {'form': form,
                              'firm': firm},
                              context_instance=RequestContext(request))


<form enctype="multipart/form-data" method="post" action="/">
  {{ form.as_p }}
  <p class="submit"><input type="submit" /></p>
</form>