diff --git a/nodepool/driver/openstack/config.py b/nodepool/driver/openstack/config.py
index 1fe030faa..5aaf53c81 100644
--- a/nodepool/driver/openstack/config.py
+++ b/nodepool/driver/openstack/config.py
@@ -69,14 +69,6 @@ class ProviderCloudImage(ConfigValue):
     def __repr__(self):
         return "<ProviderCloudImage %s>" % self.name
 
-    @property
-    def external(self):
-        '''External identifier to pass to the cloud.'''
-        if self.image_id:
-            return dict(id=self.image_id)
-        else:
-            return self.image_name or self.name
-
     @property
     def external_name(self):
         '''Human readable version of external.'''
diff --git a/nodepool/driver/openstack/handler.py b/nodepool/driver/openstack/handler.py
index 6fe2128b4..acc8fd043 100644
--- a/nodepool/driver/openstack/handler.py
+++ b/nodepool/driver/openstack/handler.py
@@ -76,6 +76,8 @@ class OpenStackNodeLauncher(NodeLauncher):
                 )
 
             config_drive = diskimage.config_drive
+            # Using a dict with the ID bypasses an image search during
+            # server creation.
             image_external = dict(id=cloud_image.external_id)
             image_id = "{path}/{upload_id}".format(
                 path=self.handler.zk._imageUploadPath(
@@ -92,7 +94,13 @@ class OpenStackNodeLauncher(NodeLauncher):
             # launch using unmanaged cloud image
             config_drive = self.label.cloud_image.config_drive
 
-            image_external = self.label.cloud_image.external
+            if self.label.cloud_image.image_id:
+                # Using a dict with the ID bypasses an image search during
+                # server creation.
+                image_external = dict(id=self.label.cloud_image.image_id)
+            else:
+                image_external = self.label.cloud_image.external_name
+
             image_id = self.label.cloud_image.name
             image_name = self.label.cloud_image.name
             username = self.label.cloud_image.username
diff --git a/nodepool/driver/openstack/provider.py b/nodepool/driver/openstack/provider.py
index 62fe6ade4..550e2eaa7 100755
--- a/nodepool/driver/openstack/provider.py
+++ b/nodepool/driver/openstack/provider.py
@@ -388,7 +388,14 @@ class OpenStackProvider(Provider):
     def labelReady(self, label):
         if not label.cloud_image:
             return False
-        image = self.getImage(label.cloud_image.external)
+
+        # If an image ID was supplied, we'll assume it is ready since
+        # we don't currently have a way of validating that (except during
+        # server creation).
+        if label.cloud_image.image_id:
+            return True
+
+        image = self.getImage(label.cloud_image.external_name)
         if not image:
             self.log.warning(
                 "Provider %s is configured to use %s as the"
diff --git a/releasenotes/notes/unmanaged_image_id-cf916620abc630e4.yaml b/releasenotes/notes/unmanaged_image_id-cf916620abc630e4.yaml
new file mode 100644
index 000000000..5bb1a35c2
--- /dev/null
+++ b/releasenotes/notes/unmanaged_image_id-cf916620abc630e4.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    For pre-existing cloud images (not managed by nodepool), referencing
+    them by ID was failing since they could not be found with this data,
+    only by name.