diff --git a/sparkpost/transmissions.py b/sparkpost/transmissions.py
index 284b0ed..a88b140 100644
--- a/sparkpost/transmissions.py
+++ b/sparkpost/transmissions.py
@@ -79,8 +79,9 @@ def _translate_keys(self, **kwargs):
             attachments)
 
         inline_images = kwargs.get('inline_images', [])
-        model['content']['inline_images'] = self._extract_attachments(
-            inline_images)
+        if inline_images:
+            model['content']['inline_images'] = self._extract_attachments(
+                inline_images)
 
         return model