diff --git a/imagekit/imagecache.py b/imagekit/imagecache.py
index 3784957..0edc8d6 100644
--- a/imagekit/imagecache.py
+++ b/imagekit/imagecache.py
@@ -74,7 +74,7 @@ def get_default_image_cache_backend():
         except ValueError:
             raise ImproperlyConfigured("%s isn't an image cache backend module." % \
                     import_path)
-        module, classname = import_path[:dot], import_path[dot+1:]
+        module, classname = import_path[:dot], import_path[dot + 1:]
         try:
             mod = import_module(module)
         except ImportError, e:
diff --git a/imagekit/models/fields/__init__.py b/imagekit/models/fields/__init__.py
index f7c5237..81c66b3 100644
--- a/imagekit/models/fields/__init__.py
+++ b/imagekit/models/fields/__init__.py
@@ -1,3 +1,5 @@
+import os
+
 from django.db import models
 from django.db.models.signals import post_init, post_save, post_delete
 
diff --git a/imagekit/models/fields/files.py b/imagekit/models/fields/files.py
index 7e964bc..862a09a 100644
--- a/imagekit/models/fields/files.py
+++ b/imagekit/models/fields/files.py
@@ -1,7 +1,7 @@
 import os
 import datetime
 
-from django.db.models.fields.files import ImageFieldFile
+from django.db.models.fields.files import ImageField, ImageFieldFile
 from django.utils.encoding import force_unicode, smart_str
 
 
@@ -19,7 +19,7 @@ class ImageSpecFieldFile(ImageFieldFile):
         else:
             image_fields = [getattr(self.instance, f.attname) for f in \
                     self.instance.__class__._meta.fields if \
-                    isinstance(f, models.ImageField)]
+                    isinstance(f, ImageField)]
             if len(image_fields) == 0:
                 raise Exception('%s does not define any ImageFields, so your' \
                         ' %s ImageSpecField has no image to act on.' % \
diff --git a/imagekit/processors/resize.py b/imagekit/processors/resize.py
index 1838e73..923877a 100644
--- a/imagekit/processors/resize.py
+++ b/imagekit/processors/resize.py
@@ -154,7 +154,7 @@ class Fit(object):
                 img = BasicResize(new_dimensions[0],
                         new_dimensions[1]).process(img)
         if self.mat_color:
-            new_img = Image.new('RGBA', (self.width, self.height),  self.mat_color)
+            new_img = Image.new('RGBA', (self.width, self.height), self.mat_color)
             new_img.paste(img, ((self.width - img.size[0]) / 2, (self.height - img.size[1]) / 2))
             img = new_img
         return img