fix image hashes (possible)

generic/models.py

@@ -205,15 +205,18 @@ class SeriesImageBase(models.Model):
     def save(self, *args, **kwargs):
         """Override save method to add image hash"""
         if self.image:
-            image_hash, is_dicom = get_image_hash(self.image)
 
-            self.is_dicom = is_dicom
-            self.image_md5_hash = image_hash
+            if not self.image_md5_hash:
+                image_hash, is_dicom = get_image_hash(self.image)
+
+                self.is_dicom = is_dicom
+                self.image_md5_hash = image_hash
         
-        # Hack for tests
-        if image_hash != "12345ABCD":
-            super().save(*args, **kwargs)  # Call the "real" save() method.
+                # Hack for tests
+                if image_hash != "12345ABCD":
+                    super().save(*args, **kwargs)  # Call the "real" save() method.
 
+        super().save(*args, **kwargs)  # Call the "real" save() method.
 
 class SeriesBase(models.Model):
     info = models.TextField(