Fixes issue with non existing file, when adding image to gallery with…

… move option. Fix for magento#21978

app/code/Magento/Catalog/Model/Product/Gallery/Processor.php

@@ -191,7 +191,7 @@ public function addImage(
         $mediaGalleryData = $product->getData($attrCode);
         $position = 0;
 
-        $absoluteFilePath = $this->mediaDirectory->getAbsolutePath($file);
+        $absoluteFilePath = $this->mediaDirectory->getAbsolutePath($destinationFile);
         $imageMimeType = $this->mime->getMimeType($absoluteFilePath);
         $imageContent = $this->mediaDirectory->readFile($absoluteFilePath);
         $imageBase64 = base64_encode($imageContent);