diff --git a/fs_product_multi_image/__manifest__.py b/fs_product_multi_image/__manifest__.py
index a08483aa77..785b8018bf 100644
--- a/fs_product_multi_image/__manifest__.py
+++ b/fs_product_multi_image/__manifest__.py
@@ -5,7 +5,7 @@
     "name": "Fs Product Multi Image",
     "summary": """
         Manage multi images from extenal file system on product""",
-    "version": "16.0.1.1.6",
+    "version": "16.0.1.2.0",
     "license": "AGPL-3",
     "author": "ACSONE SA/NV,Odoo Community Association (OCA)",
     "website": "https://github.com/OCA/storage",
diff --git a/fs_product_multi_image/migrations/16.0.1.2.0/post-migrate.py b/fs_product_multi_image/migrations/16.0.1.2.0/post-migrate.py
new file mode 100644
index 0000000000..6ab8a46737
--- /dev/null
+++ b/fs_product_multi_image/migrations/16.0.1.2.0/post-migrate.py
@@ -0,0 +1,23 @@
+# Copyright 2026 ACSONE SA/NV
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+import logging
+
+try:
+    from odoo.upgrade import util
+except ImportError as error:
+    raise ImportError(
+        "This migration script requires odoo.upgrade.util.\n"
+        "Please install odoo.upgrade.util to proceed with the migration.\n"
+        "See https://github.com/odoo/upgrade-util/"
+    ) from error
+
+
+_logger = logging.getLogger(__name__)
+
+
+def migrate(cr, version):
+    if not version:
+        return
+    _logger.info("Recompute main_image_id for product.template records")
+    util.recompute_fields(cr, "product.template", ["main_image_id"], logger=_logger)
diff --git a/fs_product_multi_image/models/product_product.py b/fs_product_multi_image/models/product_product.py
index fd87e9a7d9..1e19719e05 100644
--- a/fs_product_multi_image/models/product_product.py
+++ b/fs_product_multi_image/models/product_product.py
@@ -38,6 +38,19 @@ class ProductProduct(models.Model):
         store=False,
     )
 
+    # Compatibility field for standard modules (especially website_sale)
+    # The sole purpose of this field is to provide the field image_128
+    # that can be resolved by the web controller when requested
+    # to provide the image_128 content of a product.product record.
+    # By using a related field of the same type (FSImage) as image_medium,
+    # we avoid any extra cost of computing the image_128 content
+    image_128 = FSImage(
+        string="Image 128",
+        related="image_medium",
+        readonly=True,
+        store=False,
+    )
+
     @api.depends(
         "product_tmpl_id.image_ids",
         "product_tmpl_id.image_ids.sequence",
diff --git a/fs_product_multi_image/models/product_template.py b/fs_product_multi_image/models/product_template.py
index 3ed6c44de0..6122ed916e 100644
--- a/fs_product_multi_image/models/product_template.py
+++ b/fs_product_multi_image/models/product_template.py
@@ -33,10 +33,21 @@ class ProductTemplate(models.Model):
         store=False,
     )
 
+    # Compatibility field for standard modules (especially website_sale)
+    # The sole purpose of this field is to provide the field image_128
+    # that can be resolved by the web controller when requested
+    # to provide the image_128 content of a product.product record.
+    # By using a related field of the same type (FSImage) as image_medium,
+    # we avoid any extra cost of computing the image_128 content
+    image_128 = FSImage(
+        string="Image 128",
+        related="image_medium",
+        readonly=True,
+        store=False,
+    )
+
     @api.depends("image_ids", "image_ids.sequence")
     def _compute_main_image_id(self):
         for record in self:
-            image_ids = record.image_ids.sorted(
-                key=lambda i: f"{i.sequence},{str(i.id)}"
-            )
+            image_ids = record.image_ids.sorted(key=lambda i: (i.sequence, i.id))
             record.main_image_id = image_ids and image_ids[0] or None