Bug-Fix: Tagform for items which have no webnail

views/__init__.py

                 messages.info(request, _('Thanks for adding a Tag to %s') % w.name)
                 return redirect(get_next(request))
         else:
-            form = TagForm(factor_to_original=context['factor_to_original'])
+            form = TagForm(factor_to_original=context.get('factor_to_original'))
         context['form'] = form
         return render(request, 'pygal/tagedit.html', context=context)