diff --git a/imagekit/registry.py b/imagekit/registry.py
index e746f0c..3a998f0 100644
--- a/imagekit/registry.py
+++ b/imagekit/registry.py
@@ -44,7 +44,9 @@ class GeneratorRegistry(object):
 
     def before_access_receiver(self, sender, file, **kwargs):
         generator = file.generator
-        if generator in self._generators.values():
+
+        # FIXME: I guess this means you can't register functions?
+        if generator.__class__ in self._generators.values():
             # Only invoke the strategy method for registered generators.
             call_strategy_method(generator, 'before_access', file=file)