diff --git a/config/clusters/hhmi/common.values.yaml b/config/clusters/hhmi/common.values.yaml
index c3ce6d651e..59ace54b16 100644
--- a/config/clusters/hhmi/common.values.yaml
+++ b/config/clusters/hhmi/common.values.yaml
@@ -39,6 +39,13 @@ basehub:
           profile_options:
             image:
               display_name: Image
+              unlisted_choice:
+                enabled: True
+                display_name: "Custom image"
+                validation_regex: "^.+:.+$"
+                validation_message: "Must be a publicly available docker image, of form <image-name>:<tag>"
+                kubespawner_override:
+                  image: "{value}"
               choices:
                 spyglass:
                   display_name: Spyglass-NWB