diff --git a/core/nwb.base.yaml b/core/nwb.base.yaml
index 91c8abf8..859e9045 100644
--- a/core/nwb.base.yaml
+++ b/core/nwb.base.yaml
@@ -57,6 +57,17 @@ datasets:
     doc: Description of the image.
     required: false
 
+- neurodata_type_def: ImageReferences
+  neurodata_type_inc: NWBData
+  dtype:
+    target_type: Image
+    reftype: object
+  dims:
+  - num_images
+  shape:
+  - null
+  doc: Ordered dataset of references to Image objects.
+
 groups:
 - neurodata_type_def: NWBContainer
   neurodata_type_inc: Container
@@ -246,13 +257,7 @@ groups:
     doc: Images stored in this collection.
     quantity: '+'
   - name: order_of_images
-    dims:
-    - num_images
-    shape:
-    - null
-    dtype:
-      target_type: Image
-      reftype: object
+    neurodata_type_inc: ImageReferences
     doc: Ordered dataset of references to Image objects stored in the parent group.
       Each Image object in the Images group should be stored once and only once, so
       the dataset should have the same length as the number of images.
diff --git a/core/nwb.image.yaml b/core/nwb.image.yaml
index 1a73fadc..8cec4c24 100644
--- a/core/nwb.image.yaml
+++ b/core/nwb.image.yaml
@@ -201,6 +201,10 @@ groups:
       dtype: float32
       doc: This field is unused by IndexSeries.
       required: false
+    - name: offset
+      dtype: float32
+      doc: This field is unused by IndexSeries.
+      required: false
     - name: unit
       dtype: text
       value: N/A
diff --git a/docs/format/source/format_release_notes.rst b/docs/format/source/format_release_notes.rst
index 3ce073b0..1b0bbbfb 100644
--- a/docs/format/source/format_release_notes.rst
+++ b/docs/format/source/format_release_notes.rst
@@ -16,7 +16,8 @@ Minor changes
 - Allowed ``NWBFile/stimulus/templates`` to contain ``Images`` objects. (#459)
 - Added new optional "order_of_images" dataset to ``Images`` that contains an ordered list of object references to
   ``Image`` objects stored in the same ``Images`` object. This dataset must be used if the images are referred to
-  by index, e.g., from an ``IndexSeries`` object. (#459, #518, #519)
+  by index, e.g., from an ``IndexSeries`` object. Created new neurodata type ImageReferences which should be used
+  for this dataset. (#459, #518, #519, #520)
 - Overhauled ``IndexSeries`` type (#459):
   - Fixed dtype of ``data`` dataset of ``IndexSeries`` (int32 -> uint32).
   - Updated ``unit`` attribute of ``data`` to have fixed value "N/A".