old_contents: from django.http import HttpResponse, HttpResponseNotModified
  from django.core.exceptions import ImproperlyConfigured
  from django.core.cache import caches
  from django.utils.http import http_date
  from django.views.static import was_modified_since
  
  from imagefit.conf import settings
  from imagefit.models import Image, Presets
  
  import os
  import stat
  import time
  
  
  cache = caches[settings.IMAGEFIT_CACHE_BACKEND_NAME]
  
  
  def _image_response(image):
      response = HttpResponse(
          image.render(),
          image.mimetype
      )
      response['Last-Modified'] = http_date(image.modified)
      expire_time = getattr(settings, 'IMAGEFIT_EXPIRE_HEADER', 3600*24*30)
      response['Expires'] = http_date(time.time() + expire_time)
      return response
  
  
  def resize(request, path_name, format, url):
      if path_name == 'static_resize':
          prefix = settings.STATIC_ROOT
      elif path_name == 'media_resize':
          prefix = settings.MEDIA_ROOT
      else:
          prefix = settings.IMAGEFIT_ROOT
      # remove prepending slash
      if url[0] == '/':
          url = url[1:]
      # generate Image instance
      image = Image(path=os.path.join(prefix, url))
      if not os.path.exists(image.path):
          return HttpResponse(status=404)
  
      statobj = os.stat(image.path)
      if not was_modified_since(request.META.get('HTTP_IF_MODIFIED_SINCE'),
                                statobj[stat.ST_MTIME], statobj[stat.ST_SIZE]):
          return HttpResponseNotModified(content_type=image.mimetype)
  
      if settings.IMAGEFIT_CACHE_ENABLED:
          image.cache = cache
          image.cached_name = request.META.get('PATH_INFO')
          # shortcut everything, render cached version
          if image.is_cached:
              return _image_response(image)
  
      # retrieve preset from format argument
      preset = Presets.get(format) or Presets.from_string(format)
      if not preset:
          raise ImproperlyConfigured(
              " \"%s\" is neither a \"WIDTHxHEIGHT\" format nor a key in " +
              "IMAGEFIT_PRESETS." % format
          )
  
      # Resize and cache image
      if preset.get('crop'):
          image.crop(preset.get('width'), preset.get('height'))
      else:
          image.resize(preset.get('width'), preset.get('height'))
      image.save()
  
      return _image_response(image)
  
new_contents: import os
  import stat
  import time
  
  from django.core.cache import caches
  from django.core.exceptions import ImproperlyConfigured
  from django.http import HttpResponse, HttpResponseNotModified
  from django.utils.http import http_date
  from django.views.static import was_modified_since
  
  from imagefit.conf import settings
  from imagefit.models import Image, Presets
  
  cache = caches[settings.IMAGEFIT_CACHE_BACKEND_NAME]
  
  
  def _image_response(image):
      response = HttpResponse(
          image.render(),
          image.mimetype
      )
      response['Last-Modified'] = http_date(image.modified)
      expire_time = getattr(settings, 'IMAGEFIT_EXPIRE_HEADER', 3600*24*30)
      response['Expires'] = http_date(time.time() + expire_time)
      return response
  
  
  def resize(request, path_name, format, url):
      if path_name == 'static_resize':
          prefix = settings.STATIC_ROOT
      elif path_name == 'media_resize':
          prefix = settings.MEDIA_ROOT
      else:
          prefix = settings.IMAGEFIT_ROOT
      # remove prepending slash
      if url[0] == '/':
          url = url[1:]
      # generate Image instance
      path = os.path.join(prefix, url)
      if not os.path.exists(path):
          return HttpResponse(status=404)
      image = Image(path=path)
  
      statobj = os.stat(image.path)
      if not was_modified_since(request.META.get('HTTP_IF_MODIFIED_SINCE'),
                                statobj[stat.ST_MTIME], statobj[stat.ST_SIZE]):
          return HttpResponseNotModified(content_type=image.mimetype)
  
      if settings.IMAGEFIT_CACHE_ENABLED:
          image.cache = cache
          image.cached_name = request.META.get('PATH_INFO')
          # shortcut everything, render cached version
          if image.is_cached:
              return _image_response(image)
  
      # retrieve preset from format argument
      preset = Presets.get(format) or Presets.from_string(format)
      if not preset:
          raise ImproperlyConfigured(
              " \"%s\" is neither a \"WIDTHxHEIGHT\" format nor a key in " +
              "IMAGEFIT_PRESETS." % format
          )
  
      # Resize and cache image
      if preset.get('crop'):
          image.crop(preset.get('width'), preset.get('height'))
      else:
          image.resize(preset.get('width'), preset.get('height'))
      image.save()
  
      return _image_response(image)
  
subject: Check if path exists before creating Image object