Media Gallery behavior when duplicating a product: use copied images

app/code/core/Mage/Catalog/Model/Product.php

@@ -1464,6 +1464,16 @@ public function duplicate()
             ->setSkipImagesOnDuplicate($newProduct->getSkipImagesOnDuplicate())
             ->duplicate($this->getId(), $newProduct->getId());
 
+        $attributes = $this->getTypeInstance(true)->getSetAttributes($this);
+        // duplicate media after $this->getResource()->duplicate()
+        if (!$newProduct->getSkipImagesOnDuplicate() && isset($attributes['media_gallery'])) {
+            /** @var Mage_Catalog_Model_Resource_Eav_Attribute $mediaGalleryAttribute */
+            $mediaGalleryAttribute = $attributes['media_gallery'];
+            /** @var Mage_Catalog_Model_Product_Attribute_Backend_Media $backend */
+            $backend = $mediaGalleryAttribute->getBackend();
+            $backend->duplicate($newProduct);
+        }
+
         // TODO - duplicate product on all stores of the websites it is associated with
         /*if ($storeIds = $this->getWebsiteIds()) {
             foreach ($storeIds as $storeId) {

app/code/core/Mage/Catalog/Model/Product/Attribute/Backend/Media.php

@@ -95,6 +95,10 @@
      */
     public function beforeSave($object)
     {
+        if ($object->getIsDuplicate() == true) {
+            return;
+        }
+
         $attrCode = $this->getAttribute()->getAttributeCode();
         $value = $object->getData($attrCode);
         if (!is_array($value) || !isset($value['images'])) {
@@ -120,34 +124,17 @@
         $clearImages = [];
         $newImages   = [];
         $existImages = [];
-        if ($object->getIsDuplicate() != true) {
-            foreach ($value['images'] as &$image) {
-                if (!empty($image['removed'])) {
-                    $clearImages[] = $image['file'];
-                } elseif (!isset($image['value_id'])) {
-                    $newFile = $this->_moveImageFromTmp($image['file']);
-                    $image['new_file'] = $newFile;
-                    $newImages[$image['file']] = $image;
-                    $this->_renamedImages[$image['file']] = $newFile;
-                    $image['file'] = $newFile;
-                } else {
-                    $existImages[$image['file']] = $image;
-                }
-            }
-        } else {
-            // For duplicating we need copy original images.
-            $duplicate = [];
-            foreach ($value['images'] as &$image) {
-                if (!isset($image['value_id'])) {
-                    continue;
-                }
-
-                $newFile = $this->_copyImage($image['file']);
-                $newImages[$image['file']] = [
-                    'new_file' => $newFile,
-                    'label' => $image['label'],
-                ];
-                $duplicate[$image['value_id']] = $newFile;
+        foreach ($value['images'] as &$image) {
+            if (!empty($image['removed'])) {
+                $clearImages[] = $image['file'];
+            } elseif (!isset($image['value_id'])) {
+                $newFile = $this->_moveImageFromTmp($image['file']);
+                $image['new_file'] = $newFile;
+                $newImages[$image['file']] = $image;
+                $this->_renamedImages[$image['file']] = $newFile;
+                $image['file'] = $newFile;
+            } else {
+                $existImages[$image['file']] = $image;
             }
         }
 
@@ -200,7 +187,6 @@
     public function afterSave($object)
     {
         if ($object->getIsDuplicate() == true) {
-            $this->duplicate($object);
             return;
         }
 
@@ -700,9 +686,17 @@
             return $this;
         }
 
+        $newImagesMap = [];
+        foreach ($mediaGalleryData['images'] as &$image) {
+            $newImagesMap[$image['file']] = [
+                'file' => $this->_copyImage($image['file']),
+                'old_value_id' => $image['value_id'],
+            ];
+        }
+
         $this->_getResource()->duplicate(
             $this,
-            $mediaGalleryData['duplicate'] ?? [],
+            $newImagesMap,
             $object->getOriginalId(),
             $object->getId(),
         );

app/code/core/Mage/Catalog/Model/Resource/Product/Attribute/Backend/Media.php

@@ -180,7 +180,7 @@ public function duplicate($object, $newFiles, $originalProductId, $newProductId)
             $data = [
                 'attribute_id' => $object->getAttribute()->getId(),
                 'entity_id'    => $newProductId,
-                'value'        => $newFiles[$row['value_id']] ?? $row['value'],
+                'value'        => $newFiles[$row['value']]['file'],
             ];
 
             $valueIdMap[$row['value_id']] = $this->insertGallery($data);
@@ -200,6 +200,33 @@ public function duplicate($object, $newFiles, $originalProductId, $newProductId)
             $this->insertGalleryValueInStore($row);
         }
 
+        // Duplicate product store values
+        $mediaAttributes = Mage::getModel('catalog/product')->getMediaAttributes();
+        $attributeIds = array_map(fn($attr) => $attr->getAttributeId(), $mediaAttributes);
+        $tableName = $this->getTable(['catalog/product', 'varchar']);
+        $select = $this->_getReadAdapter()->select()
+            ->from($tableName, [
+                'entity_type_id',
+                'attribute_id',
+                'store_id',
+                'value',
+            ])
+            ->where('entity_id = ?', $originalProductId)
+            ->where('attribute_id IN (?)', $attributeIds);
+
+        $attrRows = [];
+        foreach ($this->_getReadAdapter()->fetchAll($select) as $row) {
+            $attrRows[] = [
+                'entity_type_id' => $row['entity_type_id'],
+                'attribute_id' => $row['attribute_id'],
+                'store_id' => $row['store_id'],
+                'entity_id' => $newProductId,
+                'value' => $newFiles[$row['value']]['file'],
+            ];
+        }
+
+        $this->_getWriteAdapter()->insertOnDuplicate($tableName, $attrRows, ['value']);
+
         return $this;
     }