diff --git a/imagekit/imagecache/strategies.py b/imagekit/imagecache/strategies.py
index 4a3d618..cb7edd4 100644
--- a/imagekit/imagecache/strategies.py
+++ b/imagekit/imagecache/strategies.py
@@ -1,3 +1,4 @@
+from django.utils.functional import LazyObject
 from .actions import validate_now, clear_now
 from ..utils import get_singleton
 
@@ -36,7 +37,7 @@ class DictStrategy(object):
             setattr(self, k, v)
 
 
-class StrategyWrapper(object):
+class StrategyWrapper(LazyObject):
     def __init__(self, strategy):
         if isinstance(strategy, basestring):
             strategy = get_singleton(strategy, 'image cache strategy')
diff --git a/imagekit/registry.py b/imagekit/registry.py
index d74f6b1..764ba24 100644
--- a/imagekit/registry.py
+++ b/imagekit/registry.py
@@ -90,6 +90,7 @@ class SourceGroupRegistry(object):
         Relay source group signals to the appropriate spec strategy.
 
         """
+        from .files import GeneratedImageCacheFile
         source_group = sender
 
         # Ignore signals from unregistered groups.
@@ -101,7 +102,8 @@ class SourceGroupRegistry(object):
         callback_name = self._signals[signal]
 
         for spec in specs:
-            call_strategy_method(spec, callback_name, file=source)
+            file = GeneratedImageCacheFile(spec)
+            call_strategy_method(spec, callback_name, file=file)
 
 
 class CacheableRegistry(object):