diff --git a/collective/behavior/relatedmedia/behavior.py b/collective/behavior/relatedmedia/behavior.py
index b592c8e0..a2be3b00 100644
--- a/collective/behavior/relatedmedia/behavior.py
+++ b/collective/behavior/relatedmedia/behavior.py
@@ -68,6 +68,12 @@ def default_preview_scale_direction():
     )
 
 
+def default_gallery_large_image_scale():
+    return api.portal.get_registry_record(
+        "collective.behavior.relatedmedia.image_gallery_default_large_scale", default="large"
+    )
+
+
 def default_titles_as_caption():
     return api.portal.get_registry_record(
         "collective.behavior.relatedmedia.show_titles_as_caption_default", default=False
@@ -208,6 +214,12 @@ class IRelatedMediaBehavior(model.Schema):
         required=False,
     )
 
+    large_image_scale = schema.Choice(
+        title=_("Gallery default scale for large overlay image"),
+        vocabulary="plone.app.vocabularies.ImagesScales",
+        defaultFactory=default_gallery_large_image_scale,
+    )
+
     gallery_css_class = schema.Choice(
         title=_("Gallery layout"),
         description=_("Feel free to add/remove classes in your registry.xml"),
@@ -244,6 +256,7 @@ class IRelatedMediaBehavior(model.Schema):
             "first_image_scale_direction",
             "preview_scale",
             "preview_scale_direction",
+            "large_image_scale",
             "gallery_css_class",
             "related_media_base_path",
         ],
diff --git a/collective/behavior/relatedmedia/browser.py b/collective/behavior/relatedmedia/browser.py
index 4f96f41f..df42c0b8 100644
--- a/collective/behavior/relatedmedia/browser.py
+++ b/collective/behavior/relatedmedia/browser.py
@@ -86,6 +86,7 @@ def images(self):
         first_img_scales = None
         first_img_description = ""
         first_img_uuid = ""
+        large_scale = getattr(rm_behavior, "large_image_scale", "large")
         further_images = []
         gallery = {}
 
@@ -114,7 +115,7 @@ def images(self):
                 or "thumbnail",
             )
             if scale:
-                large_scale_url = first_img_scales.scale("image", scale="large").url
+                large_scale_url = first_img_scales.scale("image", scale=large_scale).url
                 gallery[first_img_uuid] = dict(
                     url=large_scale_url,
                     tag=scale.tag(
@@ -142,7 +143,7 @@ def images(self):
                 )
                 uuid = img.UID()
                 if scale:
-                    large_scale_url = scales.scale("image", scale="large").url
+                    large_scale_url = scales.scale("image", scale=large_scale).url
                     gallery[uuid] = dict(
                         url=large_scale_url,
                         tag=scale.tag(css_class="img-fluid"),
diff --git a/collective/behavior/relatedmedia/interfaces.py b/collective/behavior/relatedmedia/interfaces.py
index cc0ba66c..c39274bd 100644
--- a/collective/behavior/relatedmedia/interfaces.py
+++ b/collective/behavior/relatedmedia/interfaces.py
@@ -62,6 +62,13 @@ class IRelatedMediaSettings(Interface):
         required=False,
     )
 
+    image_gallery_default_large_scale = schema.Choice(
+        title=_("Gallery default large scale for overlay images"),
+        vocabulary="plone.app.vocabularies.ImagesScales",
+        default="large",
+        required=False,
+    )
+
     image_gallery_default_preview_scale_direction = schema.Bool(
         title=_("Default setting for cropping gallery images"),
         default=False,
diff --git a/collective/behavior/relatedmedia/profiles/default/metadata.xml b/collective/behavior/relatedmedia/profiles/default/metadata.xml
index 011d88d6..bdad7593 100644
--- a/collective/behavior/relatedmedia/profiles/default/metadata.xml
+++ b/collective/behavior/relatedmedia/profiles/default/metadata.xml
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <metadata>
-  <version>3003</version>
+  <version>3004</version>
 </metadata>
diff --git a/collective/behavior/relatedmedia/profiles/default/registry.xml b/collective/behavior/relatedmedia/profiles/default/registry.xml
index 49f9bda2..e65d4d50 100644
--- a/collective/behavior/relatedmedia/profiles/default/registry.xml
+++ b/collective/behavior/relatedmedia/profiles/default/registry.xml
@@ -38,6 +38,6 @@
     </value>
   </records>
 
-  <!-- NOTE: the relatedmediagallery Icon for TinyMCE.toolbar is added in upgrades.py -->
+  <!-- NOTE: the relatedimagesgallery Icon for TinyMCE.toolbar is added in upgrades.py -->
 
 </registry>
diff --git a/collective/behavior/relatedmedia/upgrades.zcml b/collective/behavior/relatedmedia/upgrades.zcml
index 75d5e59c..cea68a1d 100644
--- a/collective/behavior/relatedmedia/upgrades.zcml
+++ b/collective/behavior/relatedmedia/upgrades.zcml
@@ -156,4 +156,13 @@
       handler=".upgrades.update_tinymce_settings"
       />
 
+  <upgradeDepends
+      title="Configurable large image overlay scale"
+      profile="collective.behavior.relatedmedia:default"
+      source="3003"
+      destination="3004"
+      import_steps="plone.app.registry"
+      run_deps="True"
+      />
+
 </configure>