diff --git a/nodepool/builder.py b/nodepool/builder.py
index af3fb1f89..e2629a823 100644
--- a/nodepool/builder.py
+++ b/nodepool/builder.py
@@ -430,20 +430,25 @@ class CleanupWorker(BaseWorker):
         '''
         images_dir = self._config.images_dir
         diskimage = self._config.diskimages.get(image_name)
-        if not diskimage.delete_after_upload:
-            return
-        to_keep = set(diskimage.keep_image_types)
-        # Examine the currently uploaded images and determine which
-        # formats need to be kept for future uploads.
-        for provider in providers:
-            if not provider.manage_images:
-                continue
-            if image_name not in provider.diskimages:
-                continue
-            upload = self._zk.getMostRecentBuildImageUploads(
-                1, image_name, build_id, provider.name, zk.READY)
-            if not upload:
-                to_keep.add(provider.image_type)
+
+        # If the diskimage is not in the config, it can be deleted.
+        if not diskimage:
+            to_keep = set()
+        else:
+            if not diskimage.delete_after_upload:
+                return
+            to_keep = set(diskimage.keep_image_types)
+            # Examine the currently uploaded images and determine which
+            # formats need to be kept for future uploads.
+            for provider in providers:
+                if not provider.manage_images:
+                    continue
+                if image_name not in provider.diskimages:
+                    continue
+                upload = self._zk.getMostRecentBuildImageUploads(
+                    1, image_name, build_id, provider.name, zk.READY)
+                if not upload:
+                    to_keep.add(provider.image_type)
 
         base = "-".join([image_name, build_id])
         files = DibImageFile.from_image_id(images_dir, base)